CDH1 and Familial gastric cancer: The International Gastric Cancer Linkage Consortium (IGCLC) defined the clinical criteria to select patients eligible for CDH1 germline mutations: (1) two or more documented cases of gastric cancer in first- or second-degree relatives regardless of age, with at least one confirmed diffuse gastric cancer; (2) diffuse gastric cancer before age 40 years without a family history; or (3) families with diagnoses of both diffuse gastric cancer and lobular breast carcinoma, at least one before age 50 years (van der Post et al., 2015b).