This invention relates to a method for assessing risk of prostate cancer. Specifically, it relates to utilizing both Pro108 and Prostate Specific Antigen (PSA) in combination to determine the risk of prostate cancer. In addition, it is directed to a method for assessing risk of ovarian, colon, breast or stomach cancer utilizing Pro108 or specific antibodies to Pro108. The invention provides isolated anti-prostate, ovarian, colon, breast or stomach cancer antigen (Pro108) antibodies that bind to Pro108 on a mammalian cell in vivo. The invention also encompasses compositions comprising an anti-Pro108 antibody and a carrier. These compositions can be provided in an article of manufacture or a kit. Another aspect of the invention is an isolated nucleic acid encoding an anti-Pro108 antibody, as well as an expression vector comprising the isolated nucleic acid. Also provided are cells that produce the anti-Pro108 antibodies. The invention encompasses a method of producing the anti-Pro108 antibodies. Other aspects of the invention are a method of killing an Pro108-expressing cancer cell, comprising contacting Pro108 present in the ECM with an anti-Pro108 antibody and a method of alleviating or treating an Pro108-expressing cancer in a mammal, comprising administering a therapeutically effective amount of the anti-Pro108 antibody to the mammal.

Prostate Cancer
Prostate cancer is the most prevalent cancer in men and is the second leading cause of death from cancer among males in the United States. AJCC Cancer Staging Handbook 203 (Irvin D. Fleming et al. eds., 5th ed. 1998); Walter J. Burdette, Cancer: Etiology Diagnosis, and Treatment 147 (1998). In 1999, it was estimated that 37,000 men in the United States would die as result of prostate cancer. Elizabeth A. Platz et al., & Edward Giovannucci, Epidemiology of and Risk Factors for Prostate Cancer, in Management of Prostate Cancer 21 (Eric A Klein, ed. 2000). More recently, the American Cancer Society estimated there will be 230,110 new cases of prostate cancer and 29,900 deaths in 2004. American Cancer Society website: cancer.org of the world wide web. Cancer of the prostate typically occurs in older males, with a median age of 74 years for clinical diagnosis. Burdette, supra at 147. A man's risk of being diagnosed with invasive prostate cancer in his lifetime is one in six. Platz et al., supra at 21.
Although our understanding of the etiology of prostate cancer is incomplete, the results of extensive research in this area point to a combination of age, genetic and environmental/dietary factors. Platz et al., supra at 19; Burdette, supra at 147; Steven K. Clinton, Diet and Nutrition in Prostate Cancer Prevention and Therapy, in Prostate Cancer: a Multidisciplinary Guide 246-269 (Philip W. Kantoff et al. eds. 1997). Broadly speaking, genetic risk factors predisposing one to prostate cancer include race and a family history of the disease. Platz et al., supra at 19, 28-29, 32-34. Aside from these generalities, a deeper understanding of the genetic basis of prostate cancer has remained elusive. Considerable research has been directed to studying the link between prostate cancer, androgens, and androgen regulation, as androgens play a crucial role in prostate growth and differentiation. Meena Augustus et al., Molecular Genetics and Markers of Progression, in Management of Prostate Cancer 59 (Eric A Klein ed. 2000). While a number of studies have concluded that prostate tumor development is linked to elevated levels of circulating androgen (e.g., testosterone and dihydrotestosterone), the genetic determinants of these levels remain unknown. Platz et al., supra at 29-30.
Several studies have explored a possible link between prostate cancer and the androgen receptor (AR) gene, the gene product of which mediates the molecular and cellular effects of testosterone and dihydrotestosterone in tissues responsive to androgens. Id. at 30. Differences in the number of certain trinucleotide repeats in exon 1, the region involved in transactivational control, have been of particular interest. Augustus et al., supra at 60. For example, these studies have revealed that as the number of CAG repeats decreases the transactivation ability of the gene product increases, as does the risk of prostate cancer. Platz et al., supra at 30-31. Other research has focused on the α-reductase Type 2 gene, the gene which codes for the enzyme that converts testosterone into dihydrotestosterone. Id. at 30. Dihydrotestosterone has greater affinity for the AR than testosterone, resulting in increased transactivation of genes responsive to androgens. Id. While studies have reported differences among the races in the length of a TA dinucleotide repeat in the 3′ untranslated region, no link has been established between the length of that repeat and prostate cancer. Id. Interestingly, while ras gene mutations are implicated in numerous other cancers, such mutations appear not to play a significant role in prostate cancer, at least among Caucasian males. Augustus, supra at 52.
Environmental/dietary risk factors which may increase the risk of prostate cancer include intake of saturated fat and calcium. Platz et al., supra at 19, 25-26. Conversely, intake of selenium, vitamin E and tomato products (which contain the carotenoid lycopene) apparently decrease that risk. Id. at 19, 26-28 The impact of physical activity, cigarette smoking, and alcohol consumption on prostate cancer is unclear. Platz et al., supra at 23-25.
Periodic screening for prostate cancer is most effectively performed by digital rectal examination (DRE) of the prostate, in conjunction with determination of the serum level of prostate-specific antigen (PSA). Burdette, supra at 148. While the merits of such screening are the subject of considerable debate, Jerome P. Richie & Irving D. Kaplan, Screening for Prostate Cancer. The Horns of a Dilemma, in Prostate Cancer: A Multidisciplinary Guide 1-10 (Philip W. Kantoff et al. eds. 1997), the American Cancer Society and American Urological Association recommend that both of these tests be performed annually on men 50 years or older with a life expectancy of at least 10 years, and younger men at high risk for prostate cancer. Ian M. Thompson & John Foley, Screening for Prostate Cancer, in Management of Prostate Cancer 71 (Eric A Klein ed. 2000). If necessary, these screening methods may be followed by additional tests, including biopsy, ultrasonic imaging, computerized tomography, and magnetic resonance imaging. Christopher A. Haas & Martin I. Resnick, Trends in Diagnosis, Biopsy, and Imaging, in Management of Prostate Cancer 89-98 (Eric A Klein ed. 2000); Burdette, supra at 148.
Once the diagnosis of prostate cancer has been made, treatment decisions for the individual are typically linked to the stage of prostate cancer present in that individual, as well as his age and overall health. Burdette, supra at 151. One preferred classification system for staging prostate cancer was developed by the American Urological Association (AUA). Id. at 148. The AUA classification system divides prostate tumors into four broad stages, A to D, which are in turn accompanied by a number of smaller substages. Burdette, supra at 152-153; Anthony V. D+Amico et al., The Staging of Prostate Cancer, in Prostate Cancer: A Multidisciplinary Guide 41 (Philip W. Kantoff et al. eds. 1997).
Stage A prostate cancer refers to the presence of microscopic cancer within the prostate gland. D+Amico, supra at 41. This stage is comprised of two substages: A1, which involves less than four well-differentiated cancer foci within the prostate, and A2, which involves greater than three well-differentiated cancer foci or alternatively, moderately to poorly differentiated foci within the prostate. Burdette, supra at 152; D+Amico, supra at 41. Treatment for stage A1 preferentially involves following PSA levels and periodic DRE. Burdette, supra at 151. Should PSA levels rise, preferred treatments include radical prostatectomy in patients 70 years of age and younger, external beam radiotherapy for patients between 70 and 80 years of age, and hormone therapy for those over 80 years of age. Id.
Stage B prostate cancer is characterized by the presence of a palpable lump within the prostate. Burdette, supra at 152-53; D+Amico, supra at 41. This stage is comprised of three substages: B1, in which the lump is less than 2 cm and is contained in one lobe of the prostate; B2, in which the lump is greater than 2 cm yet is still contained within one lobe; and B3, in which the lump has spread to both lobes. Burdette, supra, at 152-53. For stages B1 and B2, the treatment again involves radical prostatectomy in patients 70 years of age and younger, external beam radiotherapy for patients between 70 and 80 years of age, and hormone therapy for those over 80 years of age. Id. at 151. In stage B3, radical prostatectomy is employed if the cancer is well-differentiated and PSA levels are below 15 ng/mL; otherwise, external beam radiation is the chosen treatment option. Id.
Stage C prostate cancer involves a substantial cancer mass accompanied by extraprostatic extension. Burdette, supra at 153; D'Amico, supra at 41. Like stage A prostate cancer, Stage C is comprised of two substages: substage C1, in which the tumor is relatively minimal, with minor prostatic extension, and substage C2, in which the tumor is large and bulky, with major prostatic extension. Id. The treatment of choice for both substages is external beam radiation. Burdette, supra at 151.
The fourth and final stage of prostate cancer, Stage D, describes the extent to which the cancer has metastasized. Burdette, supra at 153; D'Amico, supra at 41. This stage is comprised of four substages: (1) D0, in which acid phophatase levels are persistently high, (2) D1, in which only the pelvic lymph nodes have been invaded, (3) D2, in which the lymph nodes above the aortic bifurcation have been invaded, with or without distant metastasis, and (4) D3, in which the metastasis progresses despite intense hormonal therapy. Id. Treatment at this stage may involve hormonal therapy, chemotherapy, and removal of one or both testes. Burdette, supra at 151.
Despite the need for accurate staging of prostate cancer, current staging methodology is limited. The wide variety of biological behavior displayed by neoplasms of the prostate has resulted in considerable difficulty in predicting and assessing the course of prostate cancer. Augustus et al., supra at 47. Indeed, despite the fact that most prostate cancer patients have carcinomas that are of intermediate grade and stage, prognosis for these types of carcinomas is highly variable. Andrew A Renshaw & Christopher L. Corless, Prognostic Features in the Pathology of prostate Cancer, in Prostate Cancer: A Multidisciplinary Guide 26 (Philip W. Kantoff et al. eds. 1997). Techniques such as transrectal ultrasound, abdominal and pelvic computerized tomography, and MRI have not been particularly useful in predicting local tumor extension. D+Amico, supra at 53 (editors' comment). While the use of serum PSA in combination with the Gleason score is currently the most effective method of staging prostate cancer, id., PSA is of limited predictive value, Augustus et al., supra at 47; Renshaw et al., supra at 26, and the Gleason score is prone to variability and error, King, C. R. & Long, J. P., Int'l. J. Cancer 90(6): 326-30 (2000). As such, the current focus of prostate cancer research has been to obtain biomarkers to help better assess the progression of the disease. Augustus et al., supra at 47; Renshaw et al., supra at 26; Pettaway, C. A., Tech. Urol. 4(1): 35-42 (1998).
Accordingly, there is a great need for more sensitive and accurate methods for predicting whether a person is likely to develop prostate cancer, for diagnosing prostate cancer, for monitoring the progression of the disease, for staging the prostate cancer, for determining whether the prostate cancer has metastasized and for imaging the prostate cancer. There is also a need for better treatment of prostate cancer.
Ovarian Cancer
Cancer of the ovaries is the fourth-most common cause of cancer death in women in the United States, with more than 23,000 new cases and roughly 14,000 deaths predicted for the year 2001. Shridhar, V. et al., Cancer Res. 61(15): 5895-904 (2001); Memarzadeh, S. & Berek, J. S., J. Reprod. Med. 46(7): 621-29 (2001). The American Cancer Society estimates that there will be about 25,580 new cases of ovarian cancer in 2004 in the United States alone. Ovarian cancer will cause about 16,090 deaths in the United States in the same year. ACS Website: cancer.org of the world wide web. The incidence of ovarian cancer is of serious concern worldwide, with an estimated 191,000 new cases predicted annually. Runnebaum, I. B. & Stickeler, E., J. Cancer Res. Clin. Oncol. 127(2): 73-79 (2001). Unfortunately, women with ovarian cancer are typically asymptomatic until the disease has metastasized. Because effective screening for ovarian cancer is not available, roughly 70% of women diagnosed have an advanced stage of the cancer with a five-year survival rate of 25-30%. Memarzadeh, S. & Berek, J. S., supra; Nunns, D. et al., Obstet. Gynecol. Surv. 55(12): 746-51. Conversely, women diagnosed with early stage ovarian cancer enjoy considerably higher survival rates. Werness, B. A. & Eltabbakh, G. H., Int'l. J. Gynecol. Pathol. 20(1): 48-63 (2001). Although our understanding of the etiology of ovarian cancer is incomplete, the results of extensive research in this area point to a combination of age, genetics, reproductive, and dietary/environmental factors. Age is a key risk factor in the development of ovarian cancer: while the risk for developing ovarian cancer before the age of 30 is slim, the incidence of ovarian cancer rises linearly between ages 30 to 50, increasing at a slower rate thereafter, with the highest incidence being among septagenarian women. Jeanne M. Schilder et al., Hereditary Ovarian Cancer: Clinical Syndromes and Management, in Ovarian Cancer 182 (Stephen C. Rubin & Gregory P. Sutton eds., 2d ed. 2001).
With respect to genetic factors, a family history of ovarian cancer is the most significant risk factor in the development of the disease, with that risk depending on the number of affected family members, the degree of their relationship to the woman, and which particular first degree relatives are affected by the disease. Id. Mutations in several genes have been associated with ovarian cancer, including BRCA1 and BRCA2, both of which play a key role in the development of breast cancer, as well as hMSH2 and hMLH1, both of which are associated with hereditary non-polyposis colon cancer. Katherine Y. Look, Epidemiology, Etiology, and Screening of Ovarian Cancer, in Ovarian Cancer 169, 171-73 (Stephen C. Rubin & Gregory P. Sutton eds., 2d ed. 2001). BRCA1, located on chromosome 17, and BRCA2, located on chromosome 13, are tumor suppressor genes implicated in DNA repair; mutations in these genes are linked to roughly 10% of ovarian cancers. Id. at 171-72; Schilder et al., supra at 185-86. hMSH2 and hMLH1 are associated with DNA mismatch repair, and are located on chromosomes 2 and 3, respectively; it has been reported that roughly 3% of hereditary ovarian carcinomas are due to mutations in these genes. Look, supra at 173; Schilder et al., supra at 184, 188-89.
Reproductive factors have also been associated with an increased or reduced risk of ovarian cancer. Late menopause, nulliparity, and early age at menarche have all been linked with an elevated risk of ovarian cancer. Schilder et al., supra at 182. One theory hypothesizes that these factors increase the number of ovulatory cycles over the course of a woman's life, leading to "incessant ovulation," which is thought to be the primary cause of mutations to the ovarian epithelium. Id.; Laura J. Havrilesky & Andrew Berchuck, Molecular Alterations in Sporadic Ovarian Cancer, in Ovarian Cancer 25 (Stephen C. Rubin & Gregory P. Sutton eds., 2d ed. 2001). The mutations may be explained by the fact that ovulation results in the destruction and repair of that epithelium, necessitating increased cell division, thereby increasing the possibility that an undetected mutation will occur. Id. Support for this theory may be found in the fact pregnancy, lactation, and the use of oral contraceptives, all of which suppress ovulation, confer a protective effect with respect to developing ovarian cancer. Id.
Among dietary/environmental factors, there would appear to be an association between high intake of animal fat or red meat and ovarian cancer, while the antioxidant Vitamin A, which prevents free radical formation and also assists in maintaining normal cellular differentiation, may offer a protective effect. Look, supra at 169. Reports have also associated asbestos and hydrous magnesium trisilicate (talc), the latter of which may be present in diaphragms and sanitary napkins. Id. at 169-70.
Current screening procedures for ovarian cancer, while of some utility, are quite limited in their diagnostic ability, a problem that is particularly acute at early stages of cancer progression when the disease is typically asymptomatic yet is most readily treated. Walter J. Burdette, Cancer: Etiology, Diagnosis, and Treatment 166 (1998); Memarzadeh & Berek, supra; Runnebaum & Stickeler, supra; Werness & Eltabbakh, supra. Commonly used screening tests include biannual rectovaginal pelvic examination, radioimmunoassay to detect the CA-125 serum tumor marker, and transvaginal ultrasonography. Burdette, supra at 166.
Pelvic examination has failed to yield adequate numbers of early diagnoses, and the other methods are not sufficiently accurate. Id. One study reported that only 15% of patients who suffered from ovarian cancer were diagnosed with the disease at the time of their pelvic examination. Look, supra at 174. Moreover, the CA-125 test is prone to giving false positives in pre-menopausal women and has been reported to be of low predictive value in post-menopausal women. Id. at 174-75. Although transvaginal ultrasonography is now the preferred procedure for screening for ovarian cancer, it is unable to distinguish reliably between benign and malignant tumors, and also cannot locate primary peritoneal malignancies or ovarian cancer if the ovary size is normal. Schilder et al., supra at 194-95. While genetic testing for mutations of the BRCA1, BRCA2, hMSH2, and hMLH1 genes is now available, these tests may be too costly for some patients and may also yield false negative or indeterminate results. Schilder et al., supra at 191-94.
Other markers of interest are HE4 and mesothelin, see Urban et al. Ovarian cancer screening Hematol Oncol Clin North Am. 2003 August; 17(4):989-1005; Hellstrom et al. The HE4 (WFDC2) protein is a biomarker for ovarian carcinoma, Cancer Res. 2003 Jul. 1;63(13):3695-700; Ordonez, Application of mesothelin immunostaining in tumor diagnosis, Am J Surg Pathol. 2003 November; 27(11):1418-28.
The staging of ovarian cancer, which is accomplished through surgical exploration, is crucial in determining the course of treatment and management of the disease. AJCC Cancer Staging Handbook 187 (Irvin D. Fleming et al. eds., 5th ed. 1998); Burdette, supra at 170; Memarzadeh & Berek, supra; Shridhar et al., supra. Staging is performed by reference to the classification system developed by the International Federation of Gynecology and Obstetrics. David H. Moore, Primary Surgical Management of Early Epithelial Ovarian Carcinoma, in Ovarian Cancer 203 (Stephen C. Rubin & Gregory P. Sutton eds., 2d ed. 2001); Fleming et al. eds., supra at 188. Stage I ovarian cancer is characterized by tumor growth that is limited to the ovaries and is comprised of three substages. Id. In substage IA, tumor growth is limited to one ovary, there is no tumor on the external surface of the ovary, the ovarian capsule is intact, and no malignant cells are present in ascites or peritoneal washings. Id. Substage IB is identical to A1, except that tumor growth is limited to both ovaries. Id. Substage IC refers to the presence of tumor growth limited to one or both ovaries, and also includes one or more of the following characteristics: capsule rupture, tumor growth on the surface of one or both ovaries, and malignant cells present in ascites or peritoneal washings. Id.
Stage II ovarian cancer refers to tumor growth involving one or both ovaries, along with pelvic extension. Id. Substage IIA involves extension and/or implants on the uterus and/or fallopian tubes, with no malignant cells in the ascites or peritoneal washings, while substage IIB involves extension into other pelvic organs and tissues, again with no malignant cells in the ascites or peritoneal washings. Id. Substage IIC involves pelvic extension as in IIA or IIB, but with malignant cells in the ascites or peritoneal washings. Id.
Stage III ovarian cancer involves tumor growth in one or both ovaries, with peritoneal metastasis beyond the pelvis confirmed by microscope and/or metastasis in the regional lymph nodes. Id. Substage IIIA is characterized by microscopic peritoneal metastasis outside the pelvis, with substage IIIB involving macroscopic peritoneal metastasis outside the pelvis 2 cm or less in greatest dimension. Id. Substage IIIC is identical to IIIB, except that the metastasis is greater than 2 cm in greatest dimension and may include regional lymph node metastasis. Id. Lastly, Stage IV refers to the presence distant metastasis, excluding peritoneal metastasis. Id.
While surgical staging is currently the benchmark for assessing the management and treatment of ovarian cancer, it suffers from considerable drawbacks, including the invasiveness of the procedure, the potential for complications, as well as the potential for inaccuracy. Moore, supra at 206-208, 213. In view of these limitations, attention has turned to developing alternative staging methodologies through understanding differential gene expression in various stages of ovarian cancer and by obtaining various biomarkers to help better assess the progression of the disease. Vartiainen, J. et al., Int'l J. Cancer, 95(5): 313-16 (2001); Shridhar et al. supra; Baekelandt, M. et al., J. Clin. Oncol. 18(22): 3775-81.
The treatment of ovarian cancer typically involves a multiprong attack, with surgical intervention serving as the foundation of treatment. Dennis S. Chi & William J. Hoskins, Primary Surgical Management of Advanced Epithelial Ovarian Cancer, in Ovarian Cancer 241 (Stephen C. Rubin & Gregory P. Sutton eds., 2d ed. 2001). For example, in the case of epithelial ovarian cancer, which accounts for ˜90% of cases of ovarian cancer, treatment typically consists of: (1) cytoreductive surgery, including total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and lymphadenectomy, followed by (2) adjuvant chemotherapy with paclitaxel and either cisplatin or carboplatin. Eltabbakh, G. H. & Awtrey, C. S., Expert Op. Pharmacother. 2(10): 109-24. Despite a clinical response rate of 80% to the adjuvant therapy, most patients experience tumor recurrence within three years of treatment. Id. Certain patients may undergo a second cytoreductive surgery and/or second-line chemotherapy. Memarzadeh & Berek, supra.
From the foregoing, it is clear that procedures used for detecting, diagnosing, monitoring, staging, prognosticating, and preventing the recurrence of ovarian cancer are of critical importance to the outcome of the patient. Moreover, current procedures, while helpful in each of these analyses, are limited by their specificity, sensitivity, invasiveness, and/or their cost. As such, highly specific and sensitive procedures that would operate by way of detecting novel markers in cells, tissues, or bodily fluids, with minimal invasiveness and at a reasonable cost, would be highly desirable.
Accordingly, there is a great need for more sensitive and accurate methods for predicting whether a person is likely to develop ovarian cancer, for diagnosing ovarian cancer, for monitoring the progression of the disease, for staging the ovarian cancer, for determining whether the ovarian cancer has metastasized, for imaging the ovarian cancer and for better treatment of ovarian cancer.
Colon Cancer
Colorectal cancer is the second most common cause of cancer death in the United States and the third most prevalent cancer in both men and women. M. L. Davila & A. D. Davila, Screening for Colon and Rectal Cancer, in Colon and Rectal Cancer 47 (Peter S. Edelstein ed., 2000). The American Cancer Society estimates that there will be about 106,370 new cases of colon cancer and 40,570 new cases of rectal cancer in the 2004 in the United States alone. Colon cancer and rectal cancer will cause about 56,730 deaths combined in the United States. ACS Website: cancer.org of the world wide web. Nearly all cases of colorectal cancer arise from adenomatous polyps, some of which mature into large polyps, undergo abnormal growth and development, and ultimately progress into cancer. Davila at 55-56. This progression would appear to take at least 10 years in most patients, rendering it a readily treatable form of cancer if diagnosed early, when the cancer is localized. Davila at 56; Walter J. Burdette, Cancer: Etiology, Diagnosis, and Treatment 125 (1998).
Although our understanding of the etiology of colon cancer is undergoing continual refinement, extensive research in this area points to a combination of factors, including age, hereditary and nonhereditary conditions, and environmental/dietary factors. Age is a key risk factor in the development of colorectal cancer, Davila at 48, with men and women over 40 years of age become increasingly susceptible to that cancer, Burdette at 126. Incidence rates increase considerably in each subsequent decade of life. Davila at 48. A number of hereditary and nonhereditary conditions have also been linked to a heightened risk of developing colorectal cancer, including familial adenomatous polyposis (FAP), hereditary nonpolyposis colorectal cancer (Lynch syndrome or HNPCC), a bowel disease, diabetes mellitus, and obesity. Id. at 47; Henry T. Lynch & Jane F. Lynch, Hereditary Nonpolyposis Colorectal Cancer (Lynch Syndromes), in Colon and Rectal Cancer 67-68 (Peter S. Edelstein ed., 2000).
Environmental/dietary factors associated with an increased risk of colorectal cancer include a high fat diet, intake of high dietary red meat, and sedentary lifestyle. Davila at 47; Reddy, B. S., Prev. Med. 16(4): 460-7 (1987). Conversely, environmental/dietary factors associated with a reduced risk of colorectal cancer include a diet high in fiber, folic acid, calcium, and hormone-replacement therapy in post-menopausal women. Davila at 50-55. The effect of antioxidants in reducing the risk of colon cancer is unclear. Davila at 53.
Because colon cancer is highly treatable when detected at an early, localized stage, screening should be a part of routine care for all adults starting at age 50, especially those with first-degree relatives with colorectal cancer. One major advantage of colorectal cancer screening over its counterparts in other types of cancer is its ability to not only detect precancerous lesions, but to remove them as well. Davila at 56. The key colorectal cancer screening tests in use today are fecal occult blood test, sigmoidoscopy, colonoscopy, double-contrast barium enema, and the carcinoembryonic antigen (CEA) test. Burdette at 125; Davila at 56.
The fecal occult blood test (FOBT) screens for colorectal cancer by detecting the amount of blood in the stool, the premise being that neoplastic tissue, particularly malignant tissue, bleeds more than typical mucosa, with the amount of bleeding increasing with polyp size and cancer stage. Davila at 56-57. While effective at detecting early stage tumors, FOBT is unable to detect adenomatous polyps (premalignant lesions), and, depending on the contents of the fecal sample, is subject to rendering false positives. Davila at 56-59. Sigmoidoscopy and colonoscopy, by contrast, allow direct visualization of the bowel, and enable one to detect, biopsy, and remove adenomatous polyps. Davila at 59-60, 61. Despite the advantages of these procedures, there are accompanying downsides: sigmoidoscopy, by definition, is limited to the sigmoid colon and below, colonoscopy is a relatively expensive procedure, and both share the risk of possible bowel perforation and hemorrhaging. Davila at 59-60. Double-contrast barium enema (DCBE) enables detection of lesions better than FOBT, and almost as well a colonoscopy, but it may be limited in evaluating the winding rectosigmoid region. Davila at 60. The CEA blood test, which involves screening the blood for carcinoembryonic antigen, shares the downside of FOBT, in that it is of limited utility in detecting colorectal cancer at an early stage. Burdette at 125.
Once colon cancer has been diagnosed, treatment decisions are typically made in reference to the stage of cancer progression. A number of techniques are employed to stage the cancer (some of which are also used to screen for colon cancer), including pathologic examination of resected colon, sigmoidoscopy, colonoscopy, and various imaging techniques. AJCC Cancer Staging Handbook 84 (Irvin D. Fleming et al. eds., 5th ed. 1998); Montgomery, R. C. and Ridge, J. A., Semin. Surg. Oncol. 15(3): 143-150 (1998). Moreover, chest films, liver functionality tests, and liver scans are employed to determine the extent of metastasis. Fleming at 84. While computerized tomography and magnetic resonance imaging are useful in staging colorectal cancer in its later stages, both have unacceptably low staging accuracy for identifying early stages of the disease, due to the difficulty that both methods have in (1) revealing the depth of bowel wall tumor infiltration and (2) diagnosing malignant adenopathy. Thoeni, R. F., Radiol. Clin. N. Am. 35(2): 457-85 (1997). Rather, techniques such as transrectal ultrasound (TRUS) are preferred in this context, although this technique is inaccurate with respect to detecting small lymph nodes that may contain metastases. David Blumberg & Frank G. Opelka, Neoadjuvant and Adjuvant Therapy for Adenocarcinoma of the Rectum, in Colon and Rectal Cancer 316 (Peter S. Edelstein ed., 2000).
Several classification systems have been devised to stage the extent of colorectal cancer, including the Dukes' system and the more detailed International Union against Cancer-American Joint Committee on Cancer TNM staging system, which is considered by many in the field to be a more useful staging system. Burdette at 126-27. The TNM system, which is used for either clinical or pathological staging, is divided into four stages, each of which evaluates the extent of cancer growth with respect to primary tumor (T), regional lymph nodes (N), and distant metastasis (M). Fleming at 84-85. The system focuses on the extent of tumor invasion into the intestinal wall, invasion of adjacent structures, the number of regional lymph nodes that have been affected, and whether distant metastasis has occurred. Fleming at 81.
Stage 0 is characterized by in situ carcinoma (Tis), in which the cancer cells are located inside the glandular basement membrane (intraepithelial) or lamina propria (intramucosal). In this stage, the cancer has not spread to the regional lymph nodes (N0), and there is no distant metastasis (M0). In stage I, there is still no spread of the cancer to the regional lymph nodes and no distant metastasis, but the tumor has invaded the submucosa (T1) or has progressed further to invade the muscularis propria (T2). Stage II also involves no spread of the cancer to the regional lymph nodes and no distant metastasis, but the tumor has invaded the subserosa, or the nonperitonealized pericolic or perirectal tissues (T3), or has progressed to invade other organs or structures, and/or has perforated the visceral peritoneum (T4). Stage III is characterized by any of the T substages, no distant metastasis, and either metastasis in 1 to 3 regional lymph nodes (N1) or metastasis in four or more regional lymph nodes (N2). Lastly, stage IV involves any of the T or N substages, as well as distant metastasis. Fleming at 84-85; Burdette at 127.
Currently, pathological staging of colon cancer is preferable over clinical staging as pathological staging provides a more accurate prognosis. Pathological staging typically involves examination of the resected colon section, along with surgical examination of the abdominal cavity. Fleming at 84. Clinical staging would be a preferred method of staging were it at least as accurate as pathological staging, as it does not depend on the invasive procedures of its counterpart.
Turning to the treatment of colorectal cancer, surgical resection results in a cure for roughly 50% of patients. Irradiation is used both preoperatively and postoperatively in treating colorectal cancer. Chemotherapeutic agents, particularly 5-fluorouracil, are also powerful weapons in treating colorectal cancer. Other agents include irinotecan and floxuridine, cisplatin, levamisole, methotrexate, interferon-α, and leucovorin. Burdette at 125, 132-33. Nonetheless, thirty to forty percent of patients will develop a recurrence of colon cancer following surgical resection, which in many patients is the ultimate cause of death. Wayne De Vos, Follow-up After Treatment of Colon Cancer, Colon and Rectal Cancer 225 (Peter S. Edelstein ed., 2000). Accordingly, colon cancer patients must be closely monitored to determine response to therapy and to detect persistent or recurrent disease and metastasis.
The next few paragraphs describe the some of molecular bases of colon cancer. In the case of FAP, the tumor suppressor gene APC (adenomatous polyposis coli), chromosomally located at 5q21, has been either inactivated or deleted by mutation. Alberts et al., Molecular Biology of the Cell 1288 (3d ed. 1994). The APC protein plays a role in a number of functions, including cell adhesion, apoptosis, and repression of the c-myc oncogene. N. R. Hall & R. D. Madoff, Genetics and the Polyp-Cancer Sequence, Colon and Rectal Cancer 8 (Peter S. Edelstein, ed., 2000). Of those patients with colorectal cancer who have normal APC genes, over 65% have such mutations in the cancer cells but not in other tissues. Alberts et al., supra at 1288. In the case of HPNCC, patients manifest abnormalities in the tumor suppressor gene HNPCC, but only about 15% of tumors contain the mutated gene. Id. A host of other genes have also been implicated in colorectal cancer, including the K-ras, N-ras, H-ras and c-myc oncogenes, and the tumor suppressor genes DCC (deleted in colon carcinoma) and p53. Hall & Madoff, supra at 8-9; Alberts et al., supra at 1288.
Abnormalities in Wg/Wnt signal transduction pathway are also associated with the development of colorectal carcinoma. Taipale, J. and Beachy, P. A. Nature 411: 349-354 (2001). Wnt1 is a secreted protein gene originally identified within mouse mammary cancers by its insertion into the mouse mammary tumor virus (MMTV) gene. The protein is homologous to the wingless (Wg) gene product of Drosophila, in which it functions as an important factor for the determination of dorsal-ventral segmentation and regulates the formation of fly imaginal discs. Wg/Wnt pathway controls cell proliferation, death and differentiation. Taipal (2001). There are at least 13 members in the Wnt family. These proteins have been found expressed mainly in the central nervous system (CNS) of vertebrates as well as other tissues such as mammary and intestine. The Wnt proteins are the ligands for a family of seven transmembrane domain receptors related to the Frizzled gene product in Drosophila. Binding Wnt to Frizzled stimulates the activity of the downstream target, Dishevelled, which in turn inactivates the glycogen synthesase kinase 3β (GSK3β). Taipal (2001). Usually active GSK3β will form a complex with the adenomatous polyposis coli (APC) protein and phosphorylate another complex member, β-catenin. Once phosphorylated, β-catenin is directed to degradation through the ubiquitin pathway. When GSK3β, or APC activity is down regulated, α-catenin is accumulated in the cytoplasm and binds to the T-cell factor or lymphocyte excitation factor (Tcf/Lef) family of transcriptional factors. Binding of α-catenin to Tcf releases the transcriptional repression and induces gene transcription. Among the genes regulated by β-catenin are a transcriptional repressor Engrailed, a transforming growth factor-β, (TGF-β) family member Decapentaplegic, and the cytokine Hedgehog in Drosophila. β-Catenin also involves in regulating cell adhesion by binding to α-catenin and E-cadherin. On the other hand, binding of β-catenin to these proteins controls the cytoplasmic β-catenin level and its complexing with TCF. Taipal (2001). Growth factor stimulation and activation of c-src or v-src also regulate β-catenin level by phosphorylation of α-catenin and its related protein, p120cas. When phosphorylated, these proteins decrease their binding to E-cadherin and β-catenin resulting in the accumulation of cytoplasmic β-catenin. Reynolds, A. B. et al. Mol. Cell Biol. 14: 8333-8342 (1994). In colon cancer, c-src enzymatic activity has been shown increased to the level of v-src. Alternation of components in the Wg/Wnt pathway promotes colorectal carcinoma development. The best known modifications are to the APC gene. Nicola S et al. Hum. Mol. Genet 10:721-733 (2001). This germline mutation causes the appearance of hundreds to thousands of adenomatous polyps in the large bowel. It is the gene defect that accounts for the autosomally dominantly inherited FAP and related syndromes. The molecular alternations that occur in this pathway largely involve deletions of alleles of tumor-suppressor genes, such as APC, p53 and Deleted in Colorectal Cancer (DCC), combined with mutational activation of proto-oncogenes, especially c-Ki-ras. Aoki, T. et al. Human Mutat. 3: 342-346 (1994). All of these lead to genomic instability in colorectal cancers.
Another source of genomic instability in colorectal cancer is the defect of DNA mismatch repair (MMR) genes. Human homologues of the bacterial mutHLS complex (hMSH2, hMLH1, hPMS1, hPMS2 and hMSH6), which is involved in the DNA mismatch repair in bacteria, have been shown to cause the HNPCC (about 70-90% HNPCC) when mutated. Modrich, P. and Lahue, R. Ann Rev. Biochem. 65: 101-133 (1996); and Peltomäki, P. Hum. Mol. Genet 10: 735-740 (2001). The inactivation of these proteins leads to the accumulation of mutations and causes genetic instability that represents errors in the accurate replication of the repetitive mono-, di-, tri- and tetra-nucleotide repeats, which are scattered throughout the genome (microsatellite regions). Jass, J. R. et al. J. Gastroenterol Hepatol 17: 17-26 (2002). Like in the classic FAP, mutational activation of c-Ki-ras is also required for the promotion of MSI in the alternative HNPCC. Mutations in other proteins such as the tumor suppressor protein phosphatase PTEN (Zhou, X. P. et al. Hum. Mol. Genet 11: 445-450 (2002)), BAX (Buttler, L. M. Aus. N. Z. J. Surg. 69: 88-94 (1999)), Caspase-5 (Planck, M. Cancer Genet Cytogenet. 134: 46-54 (2002)), TGFβ-RII (Fallik, D. et al. Gastroenterol Clin Biol. 24: 917-22 (2000)) and IGFII-R (Giovannucci E. J. Nutr. 131: 3109S-20S (2001)) have also been found in some colorectal tumors possibly as the cause of MMR defect.
Some tyrosine kinases have been shown up-regulated in colorectal tumor tissues or cell lines like HT29. Skoudy, A. et al. Biochem J. 317 (Pt 1): 279-84 (1996). Focal adhesion kinase (FAK) and its up-stream kinase c-src and c-yes in colonic epithelia cells may play an important role in the promotion of colorectal cancers through the extracellular matrix (ECM) and integrin-mediated signaling pathways. Jessup, J. M. et al., The molecular biology of colorectal carcinoma, in: The Molecular Basis of Human Cancer, 251-268 (Coleman W. B. and Tsongalis G. J. Eds. 2002). The formation of c-src/FAK complexes may coordinately deregulate VEGF expression and apoptosis inhibition. Recent evidences suggest that a specific signal-transduction pathway for cell survival that implicates integrin engagement leads to FAK activation and thus activates PI-3 kinase and akt. In turn, akt phosphorylates BAD and blocks apoptosis in epithelial cells. The activation of c-src in colon cancer may induce VEGF expression through the hypoxia pathway. Other genes that may be implicated in colorectal cancer include Cox enzymes (Ota, S. et al. Aliment Pharmacol. Ther. 16 (Suppl 2): 102-106 (2002)), estrogen (al-Azzawi, F. and Wahab, M. Climacteric 5: 3-14 (2002)), peroxisome proliferator-activated receptor-γ (PPAR-γ) (Gelman, L. et al. Cell Mol. Life Sci. 55: 932-943 (1999)), IGF-I (Giovannucci (2001)), thymine DNA glycosylase (TDG) (Hardeland, U. et al. Prog. Nucleic Acid Res. Mol. Biol. 68: 235-253 (2001)) and EGF (Mendelsohn, J. Endocrine-Related Cancer 8: 3-9 (2001)).
Gene deletion and mutation are not the only causes for development of colorectal cancers. Epigenetic silencing by DNA methylation also accounts for the lost of function of colorectal cancer suppressor genes. A strong association between MSI and CpG island methylation has been well characterized in sporadic colorectal cancers with high MSI but not in those of hereditary origin. In one experiment, DNA methylation of MLH1, CDKN2A, MGMT, THBS1, RARB, APC, and p14ARF genes has been shown in 80%, 55%, 23%, 23%, 58%, 35%, and 50% of 40 sporadic colorectal cancers with high MSI respectively. Yamamoto, H. et al. Genes Chromosomes Cancer 33: 322-325 (2002); and Kim, K. M. et al. Oncogene. 12;21(35): 5441-9 (2002). Carcinogen metabolism enzymes such as GST, NAT, CYP and MTHFR are also associated with an increased or decreased colorectal cancer risk. Pistorius, S. et al. Kongressbd Dtsch Ges Chir Kongr 118: 820-824 (2001); and Potter, J. D. J. Natl. Cancer Inst. 91: 916-932 (1999).
From the foregoing, it is clear that procedures used for detecting, diagnosing, monitoring, staging, prognosticating, and preventing the recurrence of colorectal cancer are of critical importance to the outcome of the patient. Moreover, current procedures, while helpful in each of these analyses, are limited by their specificity, sensitivity, invasiveness, and/or their cost. As such, highly specific and sensitive procedures that would operate by way of detecting novel markers in cells, tissues, or bodily fluids, with minimal invasiveness and at a reasonable cost, would be highly desirable.
Accordingly, there is a great need for more sensitive and accurate methods for predicting whether a person is likely to develop colorectal cancer, for diagnosing colorectal cancer, for monitoring the progression of the disease, for staging the colorectal cancer, for determining whether the colorectal cancer has metastasized, and for imaging the colorectal cancer. Following accurate diagnosis, there is also a need for less invasive and more effective treatment of colorectal cancer.
Gastric Cancer
The American Cancer Society estimates that there will be about 22,710 new cases of stomach cancer in 2004 in the United States alone. Stomach cancer will cause about 11,780 deaths in the United States. ACS Website: cancer.org of the world wide web. As recent as 2001 gastric cancer was estimated to rank as the thirteenth most common and the eighth most deadly cancer in the United States. AJCC Cancer Staging Handbook 71 (Irvin D. Fleming et al. eds., 5th ed. 1998). Due to a dramatic decline in the United States over the last four decades, stomach cancer was estimated to account for 2.5% of deaths from cancer in the United States in 1997, with roughly 22,000 new cases and 14,000 deaths estimated for that year. Roderich E. Schwarz, Surgical Management of Gastric Cancer: The Western Experience, in Management of Upper Gastrointestinal Cancer 83-84 (John M. Daly et al. eds. 1999). However, stomach cancer persists in being responsible for considerable mortality rates in Asia, Europe and South America. Walter J. Burdette, Cancer: Etiology, Diagnosis, and Treatment 91 (1998). In Japan for example, gastric cancer accounts for roughly one-half of the cancer deaths in men and one-third of those in women. Id. Overall, patients diagnosed with gastric cancer have an approximate 5-year survival rate of around 25-30%. J. Rüdiger Siewert et al., Early Gastric Cancer, in Management of Upper Gastrointestinal Cancer 136 (John M. Daly et al. eds. 1999).
Although our understanding of the etiology of gastric cancer is undergoing continual refinement, research in this area points to several risk factors, including various stomach diseases, diet, occupation, and genetic factors. Burdette, supra at 91. In the case of stomach diseases, stomach polyps, atrophic gastritis and metaplasia, hyperplasia related to Menetrier's disease, Helicobacter pylori infection, ulcers, and operations to the stomach have all been associated with an increased incidence of stomach cancer. Id. Dietary nitrate ingestion, which results in nitrosamine production in the stomach, as well as the intake of smoked meats, are also suspected as contributing factors. Id.; Fleming et al. eds., supra at 71. From an occupational standpoint, those who work in the metalworking, painting, fishing, ceramic, and printing industries all appear to have an elevated risk of acquiring stomach cancer. Burdette, supra at 91. From a genetic standpoint, gastric carcinomas are believed to occur through two genetic pathways: (1) chromosomal deletions that involve tumor suppressor genes and (2) microsatellite instability which targets the mononucleotide segments in coding regions of genes related to cancer. Rhyu, M. G., J. Korean Med. Sci. 13(4): 339-49 (1998). A variation in the N-acetyltransferase 1 gene has also been linked to elevated risk of gastric cancer. Boissy, R. J. et al., Int'l J. Cancer 87(4): 507-11 (2000).
Like many cancers, gastric cancer is more readily treatable when detected early. Patients diagnosed with early gastric cancer that follow proper treatment have survival rates that match healthy control patients of the same age. Siewert, supra at 136. Unfortunately, the symptoms and clinical manifestations of gastric cancer typically do not appear early in the course of the disease, and the majority of patients have symptoms of the disease for six months or more prior to diagnosis. Burdette, supra at 93. Accordingly, effective screening devices are crucial in diagnosing the disease early and in effecting proper treatment.
Following an initial assessment of a potential gastric cancer patient's symptoms, which may include, inter alia, indigestion, abdominal discomfort, dysphagia, nausea, anorexia, flatulence, weight loss, melena, the presence of a palpable mass, anemia, and enlarged lymph nodes, id., a physician may perform various screening tests. These tests include scanning for the presence of elevated levels of carcinoembryonic and oncofetal antigens, achlorhydria, blood in the stool, and cytologic analysis of gastric washings. Id. Unfortunately, in the case of the first three tests, positive results are not necessarily obtained when gastric cancer is present, or false positives may result due to the presence of other conditions. Id. A certain diagnosis is typically achieved by way of endoscopy and/or radiography using barium contrast medium. Id.; Schwarz, supra at 87. Ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) are additionally useful in determining the extent of metastasis. Burdette, supra at 94.
Once gastric cancer has been diagnosed, treatment decisions are made in reference to the stage of cancer progression. Iain G. Martin, Staging of Esophageal and Gastric Cancer, in Management of Upper Gastrointestinal Cancer 3 (John M. Daly et al. eds. 1999). Accurate staging has become even more vital to a successful treatment regimen in view of the present trend toward multi-modal therapy for gastric cancer, and particularly neoadjuvant therapy. Id.
A number of techniques are employed to stage gastric cancer (some of which are also used to screen for gastric cancer), including endoscopic ultrasonography (EUS), CT, and MRI. Id. at 24-31. EUS is the only method of staging capable of providing accurate data regarding the tumor stage (T stage) of gastric cancer, and its overall accuracy for gathering data regarding the lymph nodal stage of gastric cancer is about 70% Id. at 27-28. EUS, however, is limited for several reasons: (1) roughly 15% of patients present with non-traversable lesions, (2) there are regions of the stomach in which it is difficult to obtain high quality images, and (3) it has difficulty in discerning particular types of cancerous lesions. Id. at 27. CT scanning is of some utility when used in combination with other techniques, but it is too inaccurate to be used alone for several reasons: (1) it is limited in its ability to assess the tumor stage due to its inability to distinguish between the individual layers of the gastric wall, (2) it is highly inaccurate in assessing lymph node metastasis, and (3) it is generally unhelpful in assessing peritoneal or liver metastasis. Id. at 24, 26-27. MRI, by contrast, is able to distinguish between muscle layers in the stomach, and one study suggests that MRI is able to assist in determining the extent of tumor and serosal invasion with considerable accuracy. Id. at 27. Nonetheless, other studies have indicated that MRI has little to offer to supplement a CT assessment. Id.
The development of staging through the techniques of molecular biology is still in its infancy, but some progress in this area has been made. For example, researchers have found that Thomsen-Friedenreich (TF) and MUC 1-TF immunoreactivity characterizes a high-risk Stage I subgroup of gastric cancer patients. Baldus, S. E. et al., Oncology 61(2): 147-55 (2001). Elevated serum levels of interleukin-2 and tumor necrosis factor-alpha have been studied as possibly useful markers for advanced gastric cancer. Forones, N. M. et al., Hepatogastroenterology 48(40): 1199-201 (2001). Likewise, elevated levels of serum soluble E-cadherin may also serve as a useful prognostic marker for stomach cancer. Chan, A. O. et al., Gut 48(6): 808-11 (2001).
The two major classification systems for staging gastric cancer are the Union Internationale Contre le Cancer's TNM system, and the system devised by the Japanese Research Society for Gastric Cancer. Id. at 18-23. The TNM system is a rather simple, and in some cases arbitrary system, which is divided into several stages, each of which evaluates the extent of cancer growth with respect to primary tumor (T), regional lymph nodes (N), and distant metastasis (M). Id. at 18, 20, 22; Fleming et al. eds., supra at 3. The Japanese system is considerably more detailed, but in some cases may be overly complex and time consuming. Martin, supra at 18-20, 22-23. Because most countries other than Japan have adopted the TNM system, id. at 23, that system will be discussed further here.
Stage 0 is characterized by carcinoma in situ (Tis, an intra-epithelial tumor that has not invaded the lamina propria), and stage IA involves tumor invasion of the lamina propria or submucosa (T1); neither stage involves metastasis to the regional lymph nodes (N0) nor distant metastasis (MO). Fleming et al. eds., supra at 73. Stage IB is the same as stage IA except that either (1) regional lymph node metastasis has occurred in 1 to 6 lymph nodes (N1) or (2) the tumor has invaded the muscularis propria or subserosa (T2). Id. Stage II gastric cancer is a bit more complex than the previous stages, involving one of three scenarios, none of which involve distant metastasis: (1) tumor category T1 and metastasis into 7 to 15 regional lymph nodes (N2), (2) tumor category T2 and nodal category N1, or (3) tumor invasion into serosa without invasion into adjacent structures (i.e., spleen, liver, transverse colon, diaphragm, adrenal gland, kidney, pancreas, small intestine, retroperitoneum, and abdominal wall) and nodal category N0. Id. Stage IIIA likewise involves one of three possible scenarios: (1) tumor category T2 and nodal category N2, (2) tumor category T3 and nodal category N3, or (3) tumor invasion into adjacent structures (T4) and nodal category N0. Id. at 73-74. Stage IIIB, however, involves tumor category T3 and nodal category N2. Id. Neither stage IIIA nor stage IIIB involves distant metastasis. Id. Stage IV is characterized by a variety permutations of tumor and nodal categories, with or without distant metastasis. Id.
Turning to the treatment of gastric cancer, surgical resection is the "mainstay" of treating gastric carcinomas but is only an option for 50% to 60% of patients. David Kelsen, Combined Modality Therapy, in Management of Upper Gastrointestinal Cancer 123 (John M. Daly et al. eds. 1999). While radiotherapy is sometimes used in conjunction with resection with some effect, gastric carcinomas are typically more resistant to radiation than are other carcinomas. Burdette, supra at 97. Likewise, chemotherapy has generally been of limited utility in treating gastric carcinomas, although neoadjuvant and adjuvant chemotherapy have been used with some success. Id. at 98; Schuhmacher, C. P. et al., Cancer 91(5): 918-27 (2001). Pre- or postoperative adjuvant therapy is currently being studied due to the considerable risk for reoccurrence, as well as the fact that systemic metastasis is commonplace. Kelsen, supra at 123. When chemotherapy is used, combinations of chemotherapeutic agents yield better results than single agents; agents used in successful combinations include 5-fluoruracil, leucovorin, adriamycin, cisplatin, mitomycin, etoposide, and semustine. Burdette, supra at 98.
From the foregoing, it is clear that procedures used for detecting, diagnosing, monitoring, staging, prognosticating, treating and preventing the recurrence of gastric cancer are of critical importance to the outcome of the patient. Moreover, current procedures, while helpful in each of these areas, are limited by their specificity, sensitivity, invasiveness, and/or their cost. As such, highly specific and sensitive procedures that would operate by way of detecting novel markers in cells, tissues, or bodily fluids, with minimal invasiveness and at a reasonable cost, would be highly desirable.
Angiogenesis in Cancer
Growth and metastasis of solid tumors are also dependent on angiogenesis. Folkman, J., 1986, Cancer Research, 46, 467-473; Folkman, J., 1989, Journal of the National Cancer Institute, 82, 4-6. It has been shown, for example, that tumors which enlarge to greater than 2 mm must obtain their own blood supply and do so by inducing the growth of new capillary blood vessels. Once these new blood vessels become embedded in the tumor, they provide a means for tumor cells to enter the circulation and metastasize to distant sites such as liver, lung or bone. Weidner, N., et al., 1991, The New England Journal of Medicine, 324(1), 1-8.
Angiogenesis, defined as the growth or sprouting of new blood vessels from existing vessels, is a complex process that primarily occurs during embryonic development. The process is distinct from vasculogenesis, in that the new endothelial cells lining the vessel arise from proliferation of existing cells, rather than differentiating from stem cells. The process is invasive and dependent upon proteolysis of the extracellular matrix (ECM), migration of new endothelial cells, and synthesis of new matrix components. Angiogenesis occurs during embryogenic development of the circulatory system; however, in adult humans, angiogenesis only occurs as a response to a pathological condition (except during the reproductive cycle in women).
Under normal physiological conditions in adults, angiogenesis takes place only in very restricted situations such as hair growth and wounding healing. Auerbach, W. and Auerbach, R., 1994, Pharmacol Ther. 63(3):265-3 11; Ribatti et al., 1991, Haematologica 76(4):3 11-20; Risau, 1997, Nature 386(6626):67 1-4. Angiogenesis progresses by a stimulus which results in the formation of a migrating column of endothelial cells. Proteolytic activity is focused at the advancing tip of this "vascular sprout", which breaks down the ECM sufficiently to permit the column of cells to infiltrate and migrate. Behind the advancing front, the endothelial cells differentiate and begin to adhere to each other, thus forming a new basement membrane. The cells then cease proliferation and finally define a lumen for the new arteriole or capillary.
Unregulated angiogenesis has gradually been recognized to be responsible for a wide range of disorders, including, but not limited to, cancer, cardiovascular disease, rheumatoid arthritis, psoriasis and diabetic retinopathy. Folkman, 1995, Nat Med 1(1):27-31; Isner, 1999, Circulation 99(13): 1653-5; Koch, 1998, Arthritis Rheum 41(6):951-62; Walsh, 1999, Rheumatology (Oxford) 38(2):103-12; Ware and Simons, 1997, Nat Med 3(2): 158-64.
Of particular interest is the observation that angiogenesis is required by solid tumors for their growth and metastases. Folkman, 1986 supra; Folkman 1990, J. Natl. Cancer Inst., 82(1) 4-6; Folkman, 1992, Semin Cancer Biol 3(2):65-71; Zetter, 1998, Annu Rev Med 49:407-24. A tumor usually begins as a single aberrant cell which can proliferate only to a size of a few cubic millimeters due to the distance from available capillary beds, and it can stay 'dormant' without further growth and dissemination for a long period of time. Some tumor cells then switch to the angiogenic phenotype to activate endothelial cells, which proliferate and mature into new capillary blood vessels. These newly formed blood vessels not only allow for continued growth of the primary tumor, but also for the dissemination and recolonization of metastatic tumor cells. The precise mechanisms that control the angiogenic switch is not well understood, but it is believed that neovascularization of tumor mass results from the net balance of a multitude of angiogenesis stimulators and inhibitors Folkman, 1995, supra.
One of the most potent angiogenesis inhibitors is endostatin identified by O'Reilly and Folkman. O'Reilly et al., 1997, Cell 88(2):277-85; O'Reilly et al., 1994, Cell 79(2):315-28. Its discovery was based on the phenomenon that certain primary tumors can inhibit the growth of distant metastases. O'Reilly and Folkman hypothesized that a primary tumor initiates angiogenesis by generating angiogenic stimulators in excess of inhibitors. However, angiogenic inhibitors, by virtue of their longer half life in the circulation, reach the site of a secondary tumor in excess of the stimulators. The net result is the growth of primary tumor and inhibition of secondary tumor. Endostatin is one of a growing list of such angiogenesis inhibitors produced by primary tumors. It is a proteolytic fragment of a larger protein: endostatin is a 20 kDa fragment of collagen XVIII (amino acid H1132-K1315 in murine collagen XVIII). Endostatin has been shown to specifically inhibit endothelial cell proliferation in vitro and block angiogenesis in vivo. More importantly, administration of endostatin to tumor-bearing mice leads to significant tumor regression, and no toxicity or drug resistance has been observed even after multiple treatment cycles. Boehm et al., 1997, Nature 390(6658):404-407. The fact that endostatin targets genetically stable endothelial cells and inhibits a variety of solid tumors makes it a very attractive candidate for anticancer therapy. Fidler and Ellis, 1994, Cell 79(2):185-8; Gastl et al., 1997, Oncology 54(3):177-84; Hinsbergh et al., 1999, Ann Oncol 10 Suppl 4:60-3. In addition, angiogenesis inhibitors have been shown to be more effective when combined with radiation and chemotherapeutic agents. Klement, 2000, J. Clin Invest, 105(8) R15-24. Browder, 2000, Cancer Res. 6-(7) 1878-86, Arap et al., 1998, Science 279(5349):377-80; Mauceri et al., 1998, Nature 394(6690):287-91.
The present invention provides alternative methods of assessing risk of, detecting or treating prostate, ovarian, colon, breast and stomach cancer that overcome the limitations of conventional therapeutic methods as well as offer additional advantages that will be apparent from the detailed description below.

Pro108 antibody compositions and methods of use and use of Pro108 to assess cancer risk


A device receives a volatile fluid, then separates the vapor phase portion from the liquid phase portion in a separation chamber, and then provides separate paths from the separation chamber to a selective outlet ring across liquid and gas orifices for each outlet in the ring, where the divided gas and liquid are recombined, thereby enhancing the equal distribution of the fluid.

In the past the agricultural ammonia industry has used a relatively small ammonia applicator mounted to the three point hitch of a tractor. The applicator was built to carry a predetermined number of applicator knives depending on the number of rows to be treated on each pass. An ammonia tank was conveniently mounted on the applicator. The ammonia was divided in a confined manifold chamber across orifices which were placed in the hose fittings that feed the knives. This manifold was part of an expansion valve that maintained a predetermined pressure depending on the quantity per acre and the tractor speed. Placed between the ammonia tank's withdrawal valve and the expansion valve was a quick opening shutoff valve which the operator used to shut down the system as he made his turns at the end of the rows.
The applicator tank was filled from a detached nurse tank by the operator. While this prior system was slow due to its small size, it was probably more consistent across the fields than today's large applicator systems. Currently used large tractors mounted with relatively large tool bars, with a nurse tank in tow, have the capability of covering large tracts of land rather rapidly. Accurate ground speed control of these tractors has made it easier to lay down a given amount of ammonia for a given area, and radar ground speed sensors have removed the error of wheel slippage. With electronic controls, we are sure of the overall quantity of ammonia a given field has received, but still no one is quite sure of where it is in the field due to the variables in the art of distribution across the tool bar.
Distribution manifolds in use prior to my invention were predominantly simple devices having a central inlet opening into a disc shaped chamber, with the hose connector outlets installed in pipe threads that open into the chamber about the periphery. In use, there were typically openings that were not required and that were plugged. The larger grains, such as corn and milo, require fewer applicator knives per tool bar width than the smaller grains like wheat and barley. A forty-five foot tool bar would be a thirteen row machine in corn, requiring a manifold with thirteen outlets with equal lengths of applicator hoses, for example, thirteen hoses of twenty-five feet in length. The same tool bar rigged for small grains could have as many as forty-five knives with forty-five hoses, each twenty-five feet in length, and the user would be applying one third the product through three and one half times as many hoses.
The number and length of hoses is important, because the two forces acting on the distribution of ammonia through a manifold and hoses are gravity and thermal energy. A compact manifold having a reasonably high pressure difference across it on level ground could have its distribution noticeably affected from an uneven heat flow into the applicator hoses, because a liquified gas like ammonia prefers to flow away from heat to a colder area. To date, there has been little fruitful work done to solve the variables in distribution.

Apparatus for dividing flows of volatile fluids such as agricultural ammonia used as fertilizer


A method of forming an air gap or gaps within solid structures and specifically semiconductor structures to reduce capacitive coupling between electrical elements such as metal lines, wherein a norbornene-type polymer is used as a sacrificial material to occupy a closed interior volume in a semiconductor structure. The sacrificial material is caused to decompose into one or more gaseous decomposition products which are removed, preferably by diffusion, through an overcoat layer. The decomposition of the sacrificial material leaves an air gap or gaps at the closed interior volume previously occupied by the norbornene-type polymer. The air gaps may be disposed between electrical leads to minimize capacitive coupling therebetween.

As a consequence of the progress made in integrated circuit technology, the spacing between the metal lines on any given plane of an integrated circuit has become less and less, now extending into the submicrometer range. By reducing the spacing between conductive members in the integrated circuit, an increase in capacitive coupling occurs. This increase in capacitive coupling causes greater crosstalk, higher capacitive losses and increased RC time constant.
In order to reduce capacitive coupling, much effort has been directed toward developing low dielectric constant (low-K) materials to replace conventional dielectric materials that are interposed between the metal lines on a given layer and between layers. Many conventional electronic insulators have dielectric constants in the 3.5 to 4.2 range. For example, silicon dioxide has a dielectric constant of 4.2 and polyimides typically have dielectric constants from 2.9 to 3.5. Some advanced polymers have dielectric constants in the 2.5 to 3.0 range. Materials in the 1.8 to 2.5 range are also known, but such materials have had associated therewith severe processing, cost and materials problems.
The lowest possible, or ideal, dielectric constant is 1.0, which is the dielectric constant of a vacuum. Air is almost as good with a dielectric constant of 1.001. With this recognition of the low dielectric constant of air, attempts have been made to fabricate semiconductor devices with air gaps between metal leads to reduce the compacitive coupling between the electrically conducting members. The air gap forming techniques that have been developed have varying degrees of complexity.
U.S. Pat. No. 4,987,101 describes a method and structure for providing an insulating electrical space between two lines on a layer of material or between lines on adjacent superposed layers of material. A base member is formed having a plurality of support members extending upwardly from the base member. A removable material is deposited on the base member and around the support members. A cap member of insulating material is then disposed over said support members and the removable material. Access openings are formed in at least one of the base member or the cap member communicating with the removable material. The removable material is removed through the access openings to thereby define a space between the cap member and the base member and between the support members. During this step a partial vacuum (in which some inert gas may be dispersed) may be created in the space vacated by the removable material. The access openings are then filled in so as to provide a sealed space between the cap member and the base member which has a very low dielectric constant.
U.S. Pat. No. 5,324,683 describes several techniques for forming air gaps or regions in a semiconductor device. The air regions are formed by either selectively removing a sacrificial spacer or by selectively removing a sacrificial layer. The air regions are sealed, enclosed or isolated by either a selective growth process or by a non-conformal deposition technique. The air regions may be formed under any pressure, gas concentration or processing condition.
The techniques disclosed in the aforesaid patents rely on holes or other passageways for effecting removal of the sacrificial material. In U.S. Pat. No. 5,461,003, a sacrificial material is removed through a porous dielectric layer. According to this patent, metal leads are formed on a substrate, after which a disposable solid layer is deposited on the metal leads and substrate. The disposable solid layer is then etched back to expose the tops of the metal leads. Then a porous dielectric layer is deposited over the metal leads and disposable layer. This is followed by removal of the disposable layer which is said to be preferably accomplished by exposing the device to oxygen or oxygen-plasma at a high temperature (>100° C.) to vaporize, or burn off, the disposable layer. The oxygen moves through the porous dielectric layer to reach and react with the disposable layer and thereby convert it to a gas that moves back out of the porous dielectric layer. Upon removal of the disposable layer, air gaps are left to provide a low dielectric constant. Finally, a non-porous dielectric layer is deposited on top of the porous dielectric layer to seal the porous dielectric layer from moisture, provide improved structural support and thermal conductivity, and passivate the porous dielectric layer. This procedure results in an air gap that does not extend the full height of the adjacent metal leads or lines. The '003 patent discloses a modified method to remedy this and increase the process margin. This modified method involves a further process step wherein an oxide layer is formed on top of the metal leads so that the disposable dielectric layer can extend higher than the metal leads.
It is also noted that the exposure of the device to an oxygen plasma which must diffuse through a porous layer is not only inefficient, it also exposes other elements of the device to a potentially damaging oxygen plasma for an extended period of time. In particular, exposure of oxygen plasma to copper lines can prove deleterious. Copper is becoming an increasingly important metal in semiconductor manufacturing due to its lower resistivity when compared to aluminum.

Fabrication of a semiconductor device with air gaps for ultra-low capacitance interconnections


A method and an equipment for heating glass in a tempering furnace provided with rollers. In a tempering furnace glass (3) is heated from above with upper resistors (4) and from below with lower resistors (5). The heating resistors (4, 5) are dimensioned such that their combined power is greater than the maximum heating power needed by the furnace, and that the resistors are controlled such that the maximum amount of resistor power being used simultaneously corresponds to the maximum heating power needed by the furnace. This allows heat to be directed at a desired place in the furnace also at the initial stage of heating, and a single resistor is efficient and fast, allowing heat to be directed quickly at places where it is needed.

Current glass tempering machines employ what are known as oscillating roller furnaces in which glass is heated mainly by radiation. In the tempering process the temperature of the glass is increased above the softening point of glass in order to enable the glass to be tempered. This temperature is between 610 and 625.degree. C. depending on the thickness of the glass. The glass is then cooled at desired speed typically using forced convection whereby air jets are blown at the glass from above and from below. This method enables high heat-transfer coefficients, necessary when thin glass is concerned in order to achieve a sufficient temperature difference between the surface and centre of the glass. Examples of oscillating roller furnaces are disclosed in Fl patents 83,072 and 86,407.
When heating glass in a tempering furnace, where the glass is oscillated in a reciprocating manner upon rollers during the entire heating process and the glass is heated with resistors located above and below the glass, heat transfer to the glass is difficult to control. A reason for this is that heat transfer from massive rollers to glass, for example, is predominant particularly at the initial heating stage. In this case t e lower surface of the glass is subjected to a greater thermal current (than) above, even if the heat transfer of the upper surface had been intensified e.g. by utilizing forced convection. This makes the edges of the glass bend upwards and the contact surface between the glass and the rollers becoming quite indefinite. Furthermore, the surface pressure at the point of contact where the glass touches the roller becomes high enough to subject the glass to optical faults, i.e. white marks and scratches, breaking the surface of the glass. Furthermore, the conditions in the furnace change during the heating period. The temperature of the glass changes relative to time and particularly the heat transfer from the rollers diminishes as the temperature of the glass approaches the temperature of the rollers and as the temperature of the rollers falls at the initial stage of the heating period when the thermal current taken up by the glass is at its highest. This causes the problem of keeping the heating of the upper and lower parts of the furnace equalized during the entire heating period.
At the start of heating, a power equal to the combined power of the resistors is connected to the furnace, i.e. each resistor is switched on at maximum heating power. In this case it is impossible to adjust the furnace, and it is impossible to control the actual relative power of the upper and lower sides because of resistor delays. In this case unevenly arranged glass loads in the furnace cause the furnace to become cooled in places comprising most glass, even though the need for heating is greatest in these places.


A control system for a feedback controlled LED driving circuit, which includes a valley detect regulator unit and a control and feedback unit. The valley detect regulator unit detects a sine-like DC voltage input by a rectification unit, and stores the electric energy in the storage capacitor when the input voltage is lower than a preset valley voltage. The stored electric energy converted into the system required voltage by a system power supply unit. The control and feedback unit electrically connect to the feedback controlled LED driving circuit, providing PFC, step dimming or color temperature adjustment for driving the LED light-emitting element and detecting a feedback signal of the LED driver circuit for controlling an output current of the LED driver circuit or providing protective measures.

1. Field of the Invention
The present invention relates to the field of a control system for the light emitting diode (LED) driving circuit, in particular with respect to a control system for the feedback controlled LED driving circuit.
2. Description of the Related Art
Recently, as the unceasing improvement in DC conversion driver technique used in light emitting diode (LED), such as various designs of linear electric power driver and switching power driver, and switching power driver comprises isolated, non-isolated and various derivatives of topology configurations of which aims at providing acceptable technical solutions to consumers in the fields of power factor, efficiency, power supply controller, light source flicker, dimming, safety regulation and cost and so on.
In terms of conventional LED driver circuit, the main problem of power supply controller lies in that it is self-powered which leads to that a transformer has to coil additional wires, slower start speed and false start resulted from current leakage of power switch may be also included. And the means of non-self-powered uses line voltage to directly reduce voltage for supplying power which wastes more electric power as well as degrades the entire conversion efficiency. In addition, regarding the conventional power factor correction (PFC), it mostly uses the waveform of AC voltage derived from analog conversion to correct the reference voltage, but the means is incapable of optimizing the power factor and current harmonics based on the adjusted current waveform adapted by various driving methods, and it also has to add extra pin to detect waveform and therefore raises the cost of controller.

Control system for feedback controlled LED driving circuit


A low temperature co-fired ceramic assembly (LTCC) with a constraining core to minimize shrinkage of outer ceramic layers during firing. The outer ceramic layers have high density circuit features. A ceramic core includes several ceramic layers. Several via holes are located in the first and second ceramic layers. Several low density circuit features are located on the ceramic layers that make up the core. Outer ceramic layers are placed top and bottom of the ceramic core. The outer ceramic layers have via holes and high density circuit features. The circuit features patterned on the ceramic layers include resistors, capacitors, circuit lines, vias, inductors, or bond pads. The ceramic core is fired first in a furnace. The outer layers are then laminated to the ceramic core and fired. The ceramic core controls the shrinkage rate of the outer ceramic layers during firing allowing higher density circuit features on the outer layers.

This invention generally relates to ceramic electronic packaging. Specifically, there is a multilayered low temperature co-fired ceramic assembly (LTCC) with a constraining core to minimize shrinkage of outer ceramic layers during firing. The outer ceramic layers have high density circuit features patterned thereon.
Various devices are well known for providing ceramic packages for semiconductor devices and passive components. One of the prior art designs is a low temperature co-fired ceramic (LTCC) substrate. The LTCC ceramic is made of layers of ceramic material, which in an unfired state, are called green tapes. Circuit lines, resistors, capacitors, bonding pads and vias are created on the surface and in holes of the green tapes by conventional thick film screening techniques. The layers are stacked on top of each other laminated and fired at a relatively low temperature in a furnace. During firing, the LTCC shrinks along the x, y and z axes typically 10-20 percent depending upon the LTCC formulation.
Despite the advantages of the prior art LTCC designs, problems occur with the registration or alignment of the circuit lines and components on the exterior surfaces during manufacturing. During firing, the shrinkage of the LTCC causes the external features to vary with respect to true position. This true position error can cause misalignment when attaching components or printing post-fire materials, resulting in a defective part that is non-repairable and has to be discarded.

Low temperature co-fired ceramic with improved registration


In some examples, a memory device may include an internal synchronization circuit that provides for double data rate operation of the memory device when external single data rate signals are provided to the memory device. The external signals may be command and/or address signals provided by an external testing circuits in some examples. The internal synchronization circuit may latch and/or delay at least some of the external signals such that different external commands are provided at the rising and falling edges of the clock signal of the memory device. The memory device may latch the external signals at both the rising and falling edges of the clock signal for double data rate operation of the memory device.

This disclosure relates generally to semiconductor devices, and more specifically to semiconductor memory devices. In particular, the disclosure relates to volatile memory, such as dynamic random access memory (DRAM). Memory operations, such as read and write operations, are performed based on timing signals provided by a clock circuit. The timing signal, also referred to as a clock signal, may be a periodic signal that oscillates between two clock levels (e.g., high and low clock levels). Different types of DRAM are designed to operate in various modes with respect to the clock signal. For example, single data rate (SDR) DRAM may perform various operations only on a rising (e.g., transitioning from the low clock level to the high clock level) or falling (e.g., transitioning from the high clock level to the low clock level) edge of the clock signal. For example, the SDR DRAM may detects (e.g., latches) commands, addresses, data, and/or other signals only on rising or falling edges of the clock signal. In contrast, double data rate (DDR) DRAM may perform various operations, such as detecting commands, addresses, data, and/or other signals, on both the rising and falling edges of the clock signal. In some applications DDR DRAM may operate at a faster rate than SDR DRAM even if both DRAM receive clock signals having a same frequency because at least some DDR DRAM operations may occur at a rate (e.g., DDR) of twice per clock cycle rather than at a rate (e.g., SDR) of once per clock cycle. DDR. Thus, DDR DRAM may provide higher throughput and/or faster performance of memory operations than SDR DRAM in some applications.
Typically, memory manufacturers test DRAM die to confirm the DRAM operates according to specifications prior to packaging and/or shipping to customers. It may be desirable to test the DRAM with testing conditions that are as similar to the operating conditions in which the DRAM will be used to help ensure the DRAM will function properly when used by the customer.

Apparatuses and methods for providing internal double data rate operation from external single data rate signals


A DDS (Direct Digital Synthesis) frequency synthesizer can be adapted to operate as a pseudo random noise generator by including a swept address ingredient that distributes (but does not eliminate) repetitive frequency components that would otherwise appear in the output of the basic DDS technique, (which fetches fixed but randomized values from a waveform memory). These residual distributed long period frequency components in the output of a swept DDS pseudo random noise generator are suppressed by making the sweep itself irregular. The noise generator includes an Address Increment Register (AIR) whose content: (1) alters the address used to fetch fixed randomized values from the waveform memory; and (2) is incremented to produce the swept address (different sequences of addresses). At some point the AIR value has been incremented as high as it will go (i.e., the end of the sweep has been reached), and the process must start over. Instead of reloading the AIR with same start value at the end of each sweep, some number of residual least significant bits are left as they were at the end of the sweep, while the remaining upper bits are indeed reloaded to the previously used start value. At the end of each next sweep the residual AIR bits are different from what they were at the end of the previous sweep, ensuring that addresses sequences in the waveform memory are less periodically revisited. These residual bits will eventually repeat, but their cycle length significantly interferes with periodic signals in the noise output having periods less than the product of the period of the sweep with the period of the recycling for the residual least significant AIR bits.

A number of scientific and engineering disciplines employ random noise as component part within certain of the techniques practiced by the discipline. This is well known, as indicated by the length of time that various kinds of noise generators have been on the market (at least fifty years). And while noise in an electronic (or other) system often occurs as an unwanted component, true random noise obeying desirable rules of spectral content over a selected bandwidth is often a difficult or expensive thing to obtain, and a variety of ways have been used to produce it. Inherently analog methods of noise generation include the use of thermionic devices, semiconductor junctions, and thermal noise within resistors. These analog methods each have their advantages and disadvantages. Disadvantages are that they share are issues of cost and alteration or deterioration over time. The advent of digital technology has led to the development of various inherently digital techniques that are not inherently analog, and that rely on DAC""s (Digital to Analog Converter""s) to change a suitable stream of pseudo random digital values into the corresponding analog waveform. These inherently digital techniques have much to recommend them for general purpose low cost use, including easy control of bandwidth and distribution statistics. These methods include the direct computation (in real time!) of random numbers from suitable functions, PRBS (Pseudo Random Binary Sequence) generators, and also an adaptation of a frequency agile synthesis technique called DDS (Direct Digital Synthesis). While conceptually elegant, direct computation for high bandwidth signals (especially Gaussian ones) requires expensive computational horsepower that may be out of proportion to the costs within the rest of the instrument (which is, say, a modestly priced function generator of the bench top test equipment variety). PRBS generators uses tapped linear feedback shift registers, and as such, consume dedicated hardware not useable for anything else, and whose feedback taps are often difficult to modify in order to bring the output into compliance with desired statistical properties. In many environments DDS is often the preferred choice for generation of pseudo random noise.
DDS is believed to have originally been developed for agile synthesis of sine waveforms, such as would be used in spread spectrum transceivers. Its adaptation to become a random noise generator is relatively simple to implement. In basic DDS, a fixed, but fairly long, sequence of digital values representing a periodic signal is stored in a waveform memory. Values are read from the waveform memory at a fixed rate, but from addresses produced in accordance with the desired output frequency. The values read are applied to a DAC whose output is then filtered by a suitable analog filter. The first step in making DDS operate as a random noise generator is to load the waveform memory with a long sequence of random digital values. To obtain different statistical distributions correspondingly different sequences of values are placed into the waveform memory. This simple adaptation of the basic DDS technique is flexible, low in cost and capable of high bandwidths, but suffers from relatively poor randomness, owing to the regularity with which the same particular random numbers that are stored in the waveform memory are played back. To fix that, basic DDS has in the past been augmented with a swept address ingredient that distributes, over a series of waveform memory playback cycles, the periodic components produced by the basic technique. The result is much improved, but alas, some users report that upon concerted effort they have detected residual long period periodic signals that are in the range of 80 dB to 100 dB below the RMS value of the overall noise signal. It would be desirable if these artifacts could be inexpensively further suppressed, and the honor and reputation of advanced DDS as a pseudo random noise generator restored. What to do?
Residual distributed long period frequency components in the output of a swept DDS pseudo random noise generator are essentially suppressed beneath measurability (say, by more 100 dB below the RMS value of the overall signal) by making the swept address itself irregular. In a preferred embodiment there is a Address Increment Register (AIR) whose content: (1) alters the address used to fetch values from the waveform memory; and (2) is incremented to produce the sweep. At some point the AIR value has been incremented as high as it will go (i.e., the end of the sweep has been reached), and the process must start over. Instead of reloading the AIR with same start value at the end of each sweep, some number of residual least significant bits are left as they were at the end of the sweep, while the remaining upper bits are indeed reloaded to the previously used start value. At the end of each next sweep the residual AIR bits are different from what they were at the end of the previous sweep. This prevents consecutive sweeps from exhibiting patterns in the addresses visited in the Waveform Memory. After the fashion of repeating digits in a rational fraction, these residual bits will eventually repeat, but their cycle length significantly interferes with periodic signals in the noise output having periods less than the product of the period of the sweep with the period of the recycling for the residual least significant AIR bits.

Reduction of periodic signals in pseudo-random noise produced with direct digital synthesis


The interchangeable wheel bearing unit has a wheel hub and two tapered roller bearings, each having an outer ring and an inner ring, between which a respective row of tapered rollers is situated, and a securing ring in at least one of the inner rings of the tapered roller bearing. To assemble the wheel bearing unit without special tools, each outer ring of the tapered roller bearings has a cylindrical extension, which runs coaxially with the wheel hub axis towards the outer face of the bearing and into which a respective seal is inserted, and a retaining element, which is supported on the corresponding inner ring and axially fixes the outer ring, is located on the opposite face of the respective tapered roller bearing from the seal.

As is known, wheel bearings and wheel hubs are highly loaded parts for wheel suspension systems on the chassis of a motor vehicle, which have to withstand a very wide variety of operating loads, in particular in the case of commercial vehicles. A high service life and maintenance free use of the wheel bearings and wheel hubs are decisive competitive advantages for the operators of commercial vehicles of this type.
What are known as insert tapered roller bearing units are used predominantly in wheel bearing units for commercial vehicles.
DE 198 33 436 A1 has disclosed a hub unit complete bearing which has a double row tapered roller bearing with an inner ring, outer rings and, between them, a multiplicity of tapered rollers which are held by a cage. Furthermore, annular seals are provided on both sides of the tapered roller bearing. An inner ring is applied to part of the external circumference of the hub; a second inner ring is formed by part of the outer side of the hub.
Now, if there is damage to the bearing of a wheel bearing unit which is constructed in this way or similarly, presently the entire wheel hub unit is exchanged and scrapped, although the wheel hub itself in fact can still be used.
Even if the mounting of a wheel bearing unit of this type is carried out, for example, in a workshop, said mounting comprises a multiplicity of mounting steps according to the prior art, as are illustrated by way of example and in a simplified manner in FIGS. 1-9, namely:
FIG. 1 cleaning of the wheel hub 2,
FIG. 2 greasing of the inner ring roller crown rings 6, 6′,
FIG. 3 pressing the outer ring 4 of the first tapered roller bearing 1 into the wheel hub 2,
FIG. 4 pressing the outer ring 4′ of the second tapered roller bearing 1′ into the wheel hub 2,
FIG. 5 placing the wheel hub 2 onto the inner ring 5 of the second tapered roller bearing 1′,
FIG. 6 inserting the inner ring 5 and the tapered roller crown ring of the first tapered roller bearing 1 into the wheel hub 2,
FIG. 7 pushing the securing ring 8 into the wheel hub 2 and latching it on the two inner rings 5, 5′,
FIG. 8 inserting the seal 12 of the first tapered roller bearing 1 into the wheel hub 2, and
FIG. 9 mounting the seal 12′ of the second tapered roller bearing 1 into the wheel hub 2.
In said mounting steps, the wheel bearing has to be rotated or turned frequently. Further disadvantages are that the outer rings are not connected fixedly to a dirt protection means or to the seals. Furthermore, two different seals and two different inner rings are often necessary.
The wheel bearing unit is greased during the mounting, with the result that high requirements have to be made of the cleanliness during the mounting process.
Furthermore, DE 198 33 436 A1 relates to a method for manufacturing said hub unit complete bearing which manages with fewer manufacturing steps.
Here, first of all first and second roller cage components are manufactured. Afterward, the first and second roller cage components are inserted into the common outer ring. Subsequently, the hub is pushed into the structural assembly comprising the first and second roller cage components and then the inner ring is mounted onto the hub. This manufacturing method is realized in a relatively complicated manner, since the outer ring and the inner ring have to be mounted separately in addition to the roller cage components.
It would be more economical, in particular for the operator of the commercial vehicle, to retain the wheel hub and to change only the defective wheel bearing or both wheel bearings. However, it is assumed that, in the case of insert wheel bearings with tapered roller bearings, the repair workshops cannot be expected to deal with the complicated and challenging dismantling and mounting of the wheel bearing units. Corresponding knowhow, special tools and absolute cleanliness would be required for mounting the wheel bearing unit, which cannot usually be presupposed in many workshops. An exchange of the complete wheel hub unit is therefore complicated and expensive.

Interchangeable wheel bearing unit, for example for commercial vehicles and method for assembling a wheel bearing unit


A device includes a control input generator and a neural network trainer. A flight simulator is configured to generate first state data responsive to a first control input from the control input generator and to provide the first state data to a first neural network to generate a candidate second control input. The control input generator is also configured to select, based on a random value, a second control input from between the candidate second control input and a randomized offset control input that is based on a random offset applied to the first control input. The flight simulator is configured to generate second state data responsive to the second control input from the control input generator. The neural network trainer is configured to update weights of the first neural network based, at least in part, on the first state data and the second state data.

Although advances in artificial intelligence and machine learning are making self-driving vehicles an achievable target, aircraft continue to be operated by pilots. Collecting data from human pilots for training an autonomous aircraft can be time consuming and costly. The collected training data that is based on previous pilot experience would not cover potential new scenarios that the aircraft could encounter.

Systems and methods for training a neural network to control an aircraft