Breast cancer type 1 susceptibility protein (BRCA1) plays a central role in DNA repair by facilitating cellular response to DNA repair. BRCA1 is required for appropriate cell cycle arrests after ionizing irradiation in both the S-phase and the G2 phase of the cell cycle. BRCA1 is part of the BRCA1-associated genome surveillance complex (BASC), which contains BRCA1, MSH2, MSH6, MLH1, ATM, BLM, PMS2 and the RAD50-MRE11-NBS1 protein complex. Defects in BRCA1 are a cause of genetic susceptibility to breast and ovarian cancers.The synthetic peptide used to raise the antibody Cat. No. 200160 is selected from a sequence within the N-term region of human BRCA1. For blocking experiments, a 10 to 100 fold molar excess to antibody is recommended.