The Epidemiology and Biostatistics Core is responsible for providing the following: 1) assistance in study design and statistical analysis to SPORE investigators; 2) developing and maintaining databases on women with breast cancer who are study subjects in the SPORE or who have potential for involvement in activities of the SPORE through being a part of a pathology or mammography database; and 3) undertaking analyses of existing databases at UCSF or other institutions affiliated with our SPORE to investigate risk factors for various types of breast cancer and to evaluate parameters of screening mammography programs for early detection of the disease. The core has served as a resource to the other SPORE projects, especially in statistical design and analysis and in developing a relational database system which permits analyses of data linked from the various projects and cores. In addition, funding from the SPORE has also made possible a variety of independent analyses. Investigators in the core have utilized UCSF's large screening mammography database to conduct studies of mammography accuracy by age group and risk factors for breast cancer. This work has resulted in two separately funded additional projects to further evaluate the accuracy of screening mammography. The Epidemiology and Biostatistics Core plans to continue providing statistical support to SPORE investigators and advocates, maintain the relational database, and pursue independent research projects in breast cancer prevention and control using existing databases and establishing new databases with independent funds.