The BRCA-1 gene codes for a nuclear phosphoprotein that plays a role in maintaining genomic stability and acts as a tumor suppressor. The normal gene plays a role in repairing breaks in DNA. If a mutation occurs in this gene the repair function may become disabled thus leading to more DNA replication errors and neoplastic growth. Current findings suggest that BRCA-1 may play an as yet undefined protective role in cells, as it is strongly expressed in epithelial cells undergoing high levels of proliferation in association with differentiation. Additional findings have determined that complete loss of BRCA-1 nuclear expression in breast cancer and the correlation with poor prognostic markers imply that the altered BRCA-1 phenotype may provide an added prognostic parameter for breast cancer and could be applied for a potential rapid screening technique to identify BRCA-1 mutations.