The objective of the Biostatistics and Bioinformatics Core is to provide design and analytical support for members of the University of Colorado Comprehensive Cancer Center (UCCC). The Core has 13 staff and several consultants from two School of Medicine departments (Preventive Medicine/Biometrics;Pharmacology) and three consortium institutions (The Children's Hospital, AMC Cancer Center, National Jewish Center). With the current configuration of personnel, the areas of expertise represented in the Core are: clinical trials, survival analysis, longitudinal and missing data analysis, psychometrics, power and sample size analysis, protocol development and review;database design, development and management;gene expression analysis;trajectory clustering;proteomics data quality control;and identification of transcription control modules. Current funding to the Core includes the CCSG (0.95 FTE), the Lung SPORE (0.85 FTE), LCBCC (0.75 FTE), and other grants and institutional support (1.18 FTE). UCCC members have continuously used Core services in research/ protocol design, data analysis for clinical trials, and for prevention, population and basic science studies. During 2004 the Core provided 5733 hours of direct consultation for 30 Cancer Center members in all 8 of the Cancer Center programs. Sixty percent of the Core's budget was funded by non-CCSG peer reviewed cancer grants or institutional funds. Since the last submission Core members participated on 13 collaborative or investigatorinitiated grants that have been funded to date for over $6 million. The large increase in the number and size of both therapeutic and control trials, as well as in their complexity, including basic and translational components, has been met by statistical and bioinformatics expertise in the Core. The bio info rmaticians hired through funding from the last grant cycle have developed the Cancer Array Informatics webtool, which provides the Cancer Center members a repository to store their microarray data and to perform basic statistical analysis. In the next 5 years, Core members will continue to collaborate with investigators in all areas of the Cancer Center, including initiatives such as the AP4, caBIG, Tissue Bank and the Roadmap Regional Translational Research Center. Our participation in these initiatives will enhance our productivity in biostatistics and bioinformatics.