program with the goal of identifying novel chemical leads and biological mechanisms. The DTP screen is a three phase screen which includes: an initial screen which first involves a single dose cytotoxicity screen with the 60 cell line assay. Those passing certain thresholds are subjected to a 5 dose screen of the same 60 cell-line panel to determine a more detailed picture of the biological activity. A second phase screen establishes the maximum tolerable dosage and involves in vivo examination of tumor regression using the hollow fiber assay. The third phase of the study is the human tumor xenograft evaluation. Active compounds are selected for testing based on several criteria: disease type specificity in the in vitro assay, unique structure, potency, and demonstration of a unique pattern of cellular cytotoxicity or cytostasis, indicating a unique mechanism of action or intracellular target. A high correlation of cytotoxicity with compounds of known biological mechanism is often predictive of the drugs mechanism of action and thus a tool to aid in the drug development and testing. It also tells if there is any unique response of the drug which is not similar to any of the standard prototype compounds in the NCI database. Leadership Notable NCI faculty Amy Berrington de González, senior investigator and radiation epidemiology branch chief. Kathryn Zoon, Principal Deputy Director, 2002 to 2004. Michael B. Sporn was the Chief of the Laboratory of Chemoprevention, 1978 to 1995. Tom Misteli, NIH Distinguished Investigator and Director of the NCI Center for Cancer Research Susan Gottesman Sankar Adhya Ira Pastan Elaine Jaffe Michael Gottesman Robert C. Gallo Michael Potter Sandra Wolin Charles J. Sherr Louis M. Staudt Gordon Zubrod Steven Rosenberg Alfred Singer, Chief of the Experimental Immunology Branch of the National Cancer Institute Xiaohong Rose Yang, senior investigator. Douglas R. Lowy, Chief, Laboratory of Cellular Oncology; NCI Principal Deputy Director, initial development, characterization, and clinical testing of the preventive virus-like particle-based HPV vaccines. Notable people Susan Shurin, senior adviser See also American Cancer Society Center caBIG, the Cancer BioInformatics Grid, a National Cancer Institute (USA) initiative to link cancer researchers and their data Cancer Information Service (CIS) European Organisation for Research and Treatment of Cancer (EORTC) Journal of the National Cancer Institute National Comprehensive Cancer Network NCI-designated Cancer Center Notes and references General references National Cancer Institute Retrieved 11 June 2010. "NCI MISSION STATEMENT". National Cancer Institute. Retrieved 18 August 2004. "THE