Since the identification of BRCA1 [3] and BRCA2 [4] in 1994 as the two main HBOC-susceptibility genes, further genes involved in DNA-repair mechanism and/or predisposing for other rare cancer predisposing syndromes have been identified as additional low or moderate risk factors for HBOC (e.g. ATM, BARD1, BRIP1, CDH1, CHEK2, NBN1, PALB2. This evidence concerns the gene BRCA1 and cancer.