Characterization of anti-BRCA2 antibodies in cell lines by Western blot analysis

BRCA2 is a tumor suppressor gene associated with familial predisposition to breast and ovarian cancer. BRCA2 has been implicated in response to DNA da mage, cell cycle control and transcription. However, the mechanisms by whic h the BRCA2 protein suppresses tumor cell growth are largely unknown. To be gin to understand the contribution of BRCA2 protein to tumorigenesis, we ev aluated the specificity of 4 anti-BRCA2 antibodies directed against several different epitopes using immunoblotting techniques. The two monoclonal ant ibodies (3E6 and 5F6) detected a specific 384-kDa protein in human breast c ancer cell lines (MCF7 and MDA-MB 231) and in a human colon carcinoma cell line (CCL 221). The two polyclonal antibodies (9433 and 9434) recognized th e 384-kDa BRCA2 protein respectively in MCF7 and in CCL 221 cells, but both BRCA2 polyclonal antibodies also cross-reacted with smaller proteins.