The breast cancer gene, BRCA1 was recently cloned an identified as a tumor suppressor gene. It was recently revealed that BRCA1 binds to the DNA repair protein, Rad51 and that BRCA1 may also respond to DNA damage. The overall goal of this proposal is to gain an understanding of BRCA1/Rad51 interaction. Specifically, the research will investigate the biochemical nature of these complexes, how DNA damage effects their association and the functional significance of the BRCA1/Rad51 complex function. It is expected that this increased understanding will yield insights into oncogenesis with ultimate therapeutic implications for the diagnosis and treatment of breast cancer.