The keywords used to find the desired articles for evaluating the significance of CDH1 (E-cadherin) mutation in cases with hereditary diffuse gastric cancer and invasive lobular breast cancer were as follows: CDH1, E-cadherin, gastric carcinoma, breast carcinoma, colorectal carcinoma, signet ring cell carcinoma - then combining the keywords for specific data and emphasis on the main subject - CDH1 and gastric carcinoma, CDH1 and colorectal carcinoma, CDH1 and breast carcinoma. Here, CDH1 is linked to signet ring cell carcinoma.