Notably, a single founder mutation in BRCA2 (c.771_775del5; commonly referred to as 999del5) accounts for the majority of hereditary cancer cases in Iceland [9], and three ancestral mutations (c.68_69delAG and c.5266dupC in BRCA1 and c.5946delT in BRCA2; 185delAG, 5382insC and 6174delT, respectively) were identified in the vast majority of families with a history of BC and OC in Ashkenazi Jews [14]. This evidence concerns the gene BRCA2 and breast cancer.