Harbouring loss-of-function (LoF) variants in BRCA1 [2] or BRCA2 [3] confers significant lifetime risk of developing OC, which accounts for 40–85% of OC cases in hereditary breast and ovarian cancer (HBOC) syndrome families and 10–15% of those not selected for age at OC diagnosis and/or family history of cancer [4]. This evidence concerns the gene BRCA1 and cancer.