although the incidence of cervical cancer has decreased with the implementation of screening programs , survival of women with locally advanced cervical cancer ( lacc ) , which includes tumors at stage ib2 to iva according to the international federation of gynecology and obstetrics ( figo ) , has remained substantially unchanged using conventional treatments . concomitant chemoradiation ( ct / rt ) has been regarded as the standard therapy for lacc patients since 1999 based on results from randomized phase iii studies . neoadjuvant chemotherapy ( nact ) followed by radical hysterectomy has also been used in europe , east asia , and latin american countries as an alternative therapeutic option . may facilitate subsequent surgery , and nact has been suggested to increase radiosensitivity and decrease hypoxic cell component . however , despite the theoretical benefits of preoperative nact , its current clinical value in lacc remains controversial . in patients who were resistant to chemotherapy , the administration of other treatments may be delayed ; therefore , it is necessary to establish some markers that can identify patients who are relatively chemoresistant . tumor hypoxia is known to be involved in resistance to chemotherapy and radiotherapy , as well as the malignant tumor phenotype , involving increased tumor growth rate , invasiveness , and metastasis . in the hypoxic microenvironment , a signaling pathway involving a key regulator of cellular response to hypoxia , termed the hypoxia inducible factor ( hif ) , hif-1 consists of a constitutively expressed hif-1 subunit and an oxygen - regulated hif-1 subunit . hif-1 regulates the cellular adaptation to hypoxia and trans - activates many genes that are associated with many cellular processes , such as energy metabolism , angiogenesis , proliferation , differentiation , and viability . many studies , including our previous study , have reported that hif-1 protein is highly expressed in cervical cancer and has a significant influence on prognosis . it has been thought that , in addition to intratumoral hypoxia , some genetic and epigenetic alterations are also part of a mechanism underlying the increased levels of hif-1 in cancer and stromal cells . interestingly , 2 single - nucleotide polymorphism ( snp ) sites ( c1772 t and g1790a ) located in the oxygen - dependent degradation ( odd)/pvhl binding domain in exon 12 of the hif-1 gene cause substantially higher transcriptional activity than the wild - type by substitution of amino acids from proline to serine and from alanine to threonine , respectively . several studies and meta - analyses have reported associations between hif-1 gene polymorphisms and several types of cancer , including cervical cancer [ 1416 ] . however , to date there have been no published studies regarding the relationship between hif-1 polymorphisms and cervical cancer treated with preoperative chemotherapy and radical surgery . in the present study we investigated the association between the c1772 t and g1790a polymorphism of the hif-1 gene and chemotherapeutic response of lacc patients who received nact and radical surgery . to the best of our knowledge , this is the first report to explore on the clinical significance of hif-1a polymorphisms in patients with lacc . retrospective data collection was performed using medical records of patients with uterine cervical carcinoma figo stage ib2 to iib who underwent platinum - based nact followed by radical hysterectomy and pelvic lymphadenectomy from january 2006 through january 2012 at the department of obstetrics and gynecology , sun yat - sen memorial hospital , sun yat - sen university . the proposed treatment and the possible alternative approaches were explained to the patients , and informed consent was obtained . the inclusion criteria were : ( 1 ) cervical cancer , confirmed by pathological examination ; ( 2 ) received 23 course of platinum - based nact followed by radical hysterectomy ; ( 3 ) figo stage ib2-iib ; ( 4 ) complete basic clinical data . the exclusion criteria were : ( 1 ) previous treatments for cervical cancer ; ( 2 ) previous or concomitant cancer ; ( 3 ) insufficient data to evaluate survival and clinical response ; and ( 4 ) insufficient tissue to analyze genotype . figo stage of cervical cancer in all patients was evaluated using pelvic examination and magnetic resonance imaging ( mri ) or computed tomography ( ct ) scanning before therapy . each cycle consisted of cisplatin ( 60 mg / m / day ) and paclitaxel ( 135 mg / m / day ) . chemotherapy was withdrawn in cases of tumor progression or in patients who did not respond after 2 cycles . two to three weeks after the final course , the response to chemotherapy was clinically evaluated by the same imaging method and by directly measuring the diameters of resected tumor blocks . after nact , the patients underwent a type iii radical hysterectomy and bilateral pelvic lymphadenectomy with or without para - aortic lymphadenectomy . postoperative radiotherapy was administered according to pathological results in the presence of histopathologic risk factors . the tumor response was evaluated according to the response evaluation criteria for solid tumors ( recst , version 1.1 )   as follows : complete response ( cr ) was defined as the absence of any residual tumor after treatment at any site level ; partial response ( pr ) was defined as at least a 30% reduction in the sum of the largest diameter of the measurable lesions ; stable disease ( sd ) was defined as neither reduction that qualified as pr nor sufficient accrual that qualified as progressive disease ( pd ) ; and pd was defined as at least a 20% increase in the sum of the largest diameter of the measurable lesions . polymerase chain - reaction ( pcr ) was performed using specific primers described by fransen et al . . the sequence of primers was : 5-tgtggccattgtaaaaactca-3 ( forward ) and 5-cttgcggaactgccttctaa-3 ( reverse ) . the pcr conditions used were : 1 cycle of 94c for 4 min , followed by 40 cycles of 94c for 1 min , 55c for 1 min , and 1 min at 72c with final extension at 72c for 10 min . for each assay , a negative control ( without dna template ) , all pcr products were further purified using a minielute pcr purification kit ( qiagen ) for commercial sequencing . the sequencing primer was the same as the forward primer used for the pcr reaction . tewantin , qld , australia ) was used for the reading of sequences on chromatograms . genetic polymorphisms and clinicopathologic parameters were assessed using the pearson chi - square test or the fisher exact test . logistic regression models were used to account for potential confounding factors associated with tumor progression . for all tests , all these statistical analyses were performed using the spss program ( spss 15.0 ; spss inc . , chicago , il ) . retrospective data collection was performed using medical records of patients with uterine cervical carcinoma figo stage ib2 to iib who underwent platinum - based nact followed by radical hysterectomy and pelvic lymphadenectomy from january 2006 through january 2012 at the department of obstetrics and gynecology , sun yat - sen memorial hospital , sun yat - sen university . the proposed treatment and the possible alternative approaches were explained to the patients , and informed consent was obtained . the inclusion criteria were : ( 1 ) cervical cancer , confirmed by pathological examination ; ( 2 ) received 23 course of platinum - based nact followed by radical hysterectomy ; ( 3 ) figo stage ib2-iib ; ( 4 ) complete basic clinical data . the exclusion criteria were : ( 1 ) previous treatments for cervical cancer ; ( 2 ) previous or concomitant cancer ; ( 3 ) insufficient data to evaluate survival and clinical response ; and ( 4 ) insufficient tissue to analyze genotype . figo stage of cervical cancer in all patients was evaluated using pelvic examination and magnetic resonance imaging ( mri ) or computed tomography ( ct ) scanning before therapy . each cycle consisted of cisplatin ( 60 mg / m / day ) and paclitaxel ( 135 mg / m / day ) . chemotherapy was withdrawn in cases of tumor progression or in patients who did not respond after 2 cycles . two to three weeks after the final course , the response to chemotherapy was clinically evaluated by the same imaging method and by directly measuring the diameters of resected tumor blocks . after nact , the patients underwent a type iii radical hysterectomy and bilateral pelvic lymphadenectomy with or without para - aortic lymphadenectomy . postoperative radiotherapy was administered according to pathological results in the presence of histopathologic risk factors . the tumor response was evaluated according to the response evaluation criteria for solid tumors ( recst , version 1.1 )   as follows : complete response ( cr ) was defined as the absence of any residual tumor after treatment at any site level ; partial response ( pr ) was defined as at least a 30% reduction in the sum of the largest diameter of the measurable lesions ; stable disease ( sd ) was defined as neither reduction that qualified as pr nor sufficient accrual that qualified as progressive disease ( pd ) ; and pd was defined as at least a 20% increase in the sum of the largest diameter of the measurable lesions . polymerase chain - reaction ( pcr ) was performed using specific primers described by fransen et al . . the sequence of primers was : 5-tgtggccattgtaaaaactca-3 ( forward ) and 5-cttgcggaactgccttctaa-3 ( reverse ) . the amplicon containing both hif-1a c1772 t and g1790a site was 147bp in length . the pcr conditions used were : 1 cycle of 94c for 4 min , followed by 40 cycles of 94c for 1 min , 55c for 1 min , and 1 min at 72c with final extension at 72c for 10 min . for each assay , a negative control ( without dna template ) was added to monitor pcr contamination . after confirming the integrity of the amplicons , all pcr products were further purified using a minielute pcr purification kit ( qiagen ) for commercial sequencing . the sequencing primer was the same as the forward primer used for the pcr reaction . chromaspro software ( technelysium pty ltd . , tewantin , qld , australia ) was used for the reading of sequences on chromatograms . genetic polymorphisms and clinicopathologic parameters were assessed using the pearson chi - square test or the fisher exact test . logistic regression models were used to account for potential confounding factors associated with tumor progression . for all tests , all these statistical analyses were performed using the spss program ( spss 15.0 ; spss inc . , chicago , il ) . a total of 162 patients were enrolled in this study according to the inclusion criteria . the median age of the patients was 47 years ( range , 2470 years ) . the genotype frequencies of the c1772 t polymorphism and the g1790a polymorphism in the hif-1 gene of the 162 cervical cancer patients are displayed in table 2 and figure 1 . the c1772 t genotype distributions were 139 cc ( 85.8% ) , 23 ct ( 14.2% ) , and 0 tt ( 0.0% ) . the g1790a genotype distributions were 151 gg ( 93.2% ) , 11 ga ( 6.8% ) , and 0 aa ( 0.0% ) . most clinicopathologic results failed to show a significant relationship with hif-1 polymorphism except for tumor grade . tumors had significantly worse differentiation in patients who had c1772 t variant after adjustment for histology type , figo stage , tumor size , doi , lvi , and lnm ( adjusted or , 2.98 ; 95% ci : 1.088.13 ; p=0.037 ) ( table 3 ) . a statistically significant association was found between polymorphisms of c1772 t and favorable response to platinum - based chemotherapy ( p=0.002 ) . logistic regression analysis showed a significantly increased chance of treatment response in patients with the c / c genotype versus the c / t genotype ( odds ratio 4.7 ; 95% ci : 1.6713.49 ; p=0.004 ) . a total of 162 patients were enrolled in this study according to the inclusion criteria . the median age of the patients was 47 years ( range , 2470 years ) . the genotype frequencies of the c1772 t polymorphism and the g1790a polymorphism in the hif-1 gene of the 162 cervical cancer patients are displayed in table 2 and figure 1 . the c1772 t genotype distributions were 139 cc ( 85.8% ) , 23 ct ( 14.2% ) , and 0 tt ( 0.0% ) . the g1790a genotype distributions were 151 gg ( 93.2% ) , 11 ga ( 6.8% ) , and 0 aa ( 0.0% ) . for analysis , variant homozygous and heterozygous subjects were grouped as t or a carriers . most clinicopathologic results failed to show a significant relationship with hif-1 polymorphism except for tumor grade . tumors had significantly worse differentiation in patients who had c1772 t variant after adjustment for histology type , figo stage , tumor size , doi , lvi , and lnm ( adjusted or , 2.98 ; 95% ci : 1.088.13 ; p=0.037 ) ( table 3 ) . a statistically significant association was found between polymorphisms of c1772 t and favorable response to platinum - based chemotherapy ( p=0.002 ) . logistic regression analysis showed a significantly increased chance of treatment response in patients with the c / c genotype versus the c / t genotype ( odds ratio 4.7 ; 95% ci : 1.6713.49 ; p=0.004 ) . the value of nact followed by surgery in cervical cancer is still controversial . despite its unclear role , it has been widely accepted that nact has a beneficial effect on cervical cancer patients who are sensitive to chemotherapy . this study aimed to evaluate the relationship between hif-1 polymorphisms and chemotherapeutic response in patients with lacc who received nact followed by radical surgery . snps of genes coding enzymes are involved in drug metabolism and transportation , and the apoptosis cascade was associated with the response to chemotherapy in various cancers . some genotypes related to dna repair have been reported to affect the response to chemotherapy . in the hypoxic microenvironment , hypoxic cancer cells acquire invasive and metastatic properties and resistance to chemotherapy in the process of adapting to hypoxia ; these properties are mediated by hifs . genetic and epigenetic alterations may also be a mechanism underlying the increased levels of hifs in cancer cells . in the present study , only c1772 recently also concluded that hif-1 c1772 t polymorphism was associated with histological grade of cancer , especially in asian cancer patients . firstly , due to limitations imposed by retrospective chart review , there were insufficient data to explore the relationship between hpv infection and hif-1 polymorphism , and some studies have reported there is an interaction between hpv and hif-1 gene . secondly , the sample size of our study was relatively small , and variant homozygotes were not found among those samples ; therefore , we could not analyze the relationship between variant homozygote and chemotherapeutic response . this is the first study to explore the relationship between hif-1 polymorphisms and response in patients undergoing neoadjuvant chemotherapy for locally advanced cervical cancer . the c1772 t polymorphism has an effect on cervical cancer patients response to chemotherapy and may be related to cervical cancer progression . our findings may help to improve management of individual patients and to enhance clinical decision making regarding nact . further studies may be necessary to explore the mechanism of c1772 t polymorphism , which affects the response of cervical cancer patients undergoing neoadjuvant chemotherapy .
backgroundthe aim of the study was to assess whether hif-1 polymorphisms have an effect on the response to chemotherapy of locally advanced cervical cancer ( lacc ) patients treated with platinum - based neoadjuvant chemotherapy ( nact ) and radical surgery.material/methodswe conducted a retrospective study in 162 lacc patients . 
 hypoxia - inducible factor 1 c1772 t and g1790a genetic polymorphisms were ascertained using direct sequencing methods.resultsthe c1772 t polymorphism was significantly related to response to chemotherapy ( p=0.002 ) , and there was an increased chance of treatment response in patients with the c / c genotype ( or=4.7 ; 95% ci : 1.6713.49 ; p=0.004 ) . 
 the c1772 t polymorphism was also associated with poor tumor grade ( adjusted or , 2.98 ; 95% ci : 1.088.13 ; p=0.037 ) . 
 however , the g1790a polymorphism was not associated with response ( p>0.05).conclusionsthe c1772 t polymorphism was significantly related to response to chemotherapy and poor tumor grade . 
 our results may help to better manage individual patients and to improve clinical decision making regarding use of nact .