This gene was first identified by Wooster who localized it to chromosome 13q12-13 and described multiple cases of breast cancer in men that showed linkage to this area.24 Families in which breast cancer has occurred and where at least one male has been affected have been reported to have a 60% to 76% chance of carrying BRCA2 mutations.25 Thus, the presence of breast cancer in men within a family with documented breast cancer indicates a high likelihood of a BRCA2 mutation. This evidence concerns the gene BRCA2 and breast cancer.