BRCA1 and breast cancer: The families with a single male breast cancer case and no other breast/ovarian cancers among first degree relatives (Group MBR) had the mutation detection rate of 4% for BRCA2 and 0% for BRCA1. Yet, when taken together, all families with male breast cancer in their family history had the mutation detection rate of 11.5% (3 positive families from 26 tested families) [38].