MSH2 and Lynch syndrome: The most striking finding was the paucity of the pathogenic variants in any of the MMR genes, resulting in Lynch syndrome (MIM: 120435), that is, MLH1, MSH2, MSH6, or PMS2, that are clearly considered as the major causes of hereditary epithelial OC in addition to BRCA1/2 alterations, with a lifetime risk of OC estimated at 6–10% [10].