Hereditary diffuse gastric cancer represents 1–3 % of all gastric cancers.2 In approximately 30 % of families with hereditary diffuse gastric cancer, germline mutations are found in the E-cadherin-1 (CDH1) tumor suppressor gene.3–6 The CDH1 gene codes for the E-cadherin protein, and loss of function of the CDH1 gene leads to diffuse gastric cancer. Here, CDH1 is linked to gastric cancer.