Screening for RAD51 and BRCA2 BRC repeat mutations in breast and ovarian cancer families.

Together, germline mutations in the two major susceptibility genes BRCA1 and BRCA2 account for approximately 20-30% and 70-80% of the familial breast and ovarian cancer cases, respectively. This indicates involvement of additional susceptibility genes, perhaps in combination with a polygenic effect. However, it is also possible that part of the mutations disrupting BRCA1 and BRCA2 function still remains to be discovered. In response to double-strand DNA damage the co-operation between RAD51 and BRCA2 is of great importance, and the conserved BRC repeat motifs in BRCA2 are crucial for this interaction. In the current study, patients belonging to 126 breast and/or ovarian cancer families were screened for RAD51 and BRCA2 BRC repeat mutations in order to uncover aberrations that may contribute to hereditary cancer susceptibility. The performed study revealed several novel alterations, however, none of them appeared to be disease-related. Thus, it seems likely that germline mutations in the highly conserved RAD51 gene are extremely rare and generally poorly tolerated.