Between 5 and 10% [5] of all BC and 13–15% of OC [6, 7] are hereditary and approximately 25% are associated with the Hereditary breast/ovarian cancer (HBOC) syndrome, caused by abnormalities in the DNA repair genes BRCA1 and BRCA2 [8]. This evidence concerns the gene BRCA1 and Hereditary breast and ovarian cancer syndrome.