) This application for a Preventive Oncology Academic Award will allow the applicant to develop as an independent researcher engaged in epidemiologic studies of cancer etiology and prevention in a defined population-based, managed care setting. This application is jointly sponsored by faculty from the Center for Health Studies at Group Health Cooperative, the Cancer Prevention Research Program of the Fred Hutchinson Cancer Research Center, and the Department of Epidemiology at the University of Washington. In this setting, Dr. Mandelson plans to pursue a four-year program that consists of academic activities, post-graduate teaching, advanced training, and three research projects. Research Projects Proposed: 1. A cross-sectional study of breast cell proliferation and mammographic density in women undergoing excisional breast biopsy. 2. An evaluation of mammography performance in elderly women. 3. A case-control study of hormone replacement therapy and adenomatous polyps. This plan is focused on three specific areas of interest: the use of biomarkers in cancer epidemiology research, cancer screening evaluation, and cancer etiology. Completion of this program will provide a strong foundation for a successful independent career in cancer control research.