For example, mutations in BRCA1 and BRCA2 confer 40–80% lifetime risk of developing breast cancer, and 11–50% of developing ovarian cancer [5]; germline variants in at least one of the DNA mismatch repair genes (eg. MSH2, MLH1, MSH6, and PMS1) affect in up to 80% of the Lynch syndrome individuals [6]; and mutations in CDH1 gene are detected in 30 to 40% of families with hereditary diffuse gastric cancer (HDGC) [7]. This evidence concerns the gene BRCA1 and Familial gastric cancer.