Because BRCA1 is a prostate cancer susceptibility gene (with an estimated risk for prostate cancer of two- to four-fold by the age of 65) [16,17,18,19], and the BRCA1 protein interacts with the BARD1 protein, we considered BARD1 to be a candidate prostate cancer susceptibility gene. Here, BRCA1 is linked to Familial prostate cancer.