) While advances in cancer genetics are occurring at rapid pace, critical questions about genetic susceptibility and prevention remain unanswered. In response to the RFA for the Cancer Genetics Network, we propose to: (1) Enroll substantial numbers of the following populations into the CGN: (a) hereditary breast, ovarian, and colon cancer families, (b) newly diagnosed high risk breast cancer patients, and (c) persons at low to moderate risk of cancer; (2) Utilize our existing networks of community-based hospitals and primary care clinics to increase CGN enrollment of African Americans and Latin Americans in the Washington, D.C. area; (3) Contribute our well-validated IRB-approved protocols for informed consent, pre-test education, and genetic counseling to the CGN; (4) Provide CGN investigators with access to our state-of-the-art laboratory technologies for diagnostic genetic analysis; (5) Utilize our existing infrastructure for cancer DNA/tissue collection, processing, and storage to contribute to basic cancer genetics research in the CGN; (6) Modify existing cancer genetics educational materials to target African Americans and develop Spanish language materials, consent forms and counseling protocols for use with Latin Americans; (7) Provide genetics education and training programs for a wide range of healthcare providers, including nurses and medical students; and (8) Contribute our expertise conducting research on the clinical, psychosocial, and economic outcomes of genetic testing for cancer susceptibility.