This paper provides a bird's-eye view both in preclinical and clinical aspects of E-cadherin germline gene (CDH1) in gastric cancer patients and their families. E-cadherin, a product of CDH1 gene, belonging to the functionally related trans-membrane glycoprotein family, is responsible for the Ca(2+)-dependent cell-cell adhesion mechanism and contributes to dissociation followed by acquisition of cell motility, which usually occurs in the first step of cancer invasion and metastasis. CDH1 gene germline mutation is common in many types of carcinoma, and occurs very frequent in hereditary gastric carcinoma (HGC) patients and their families. Recently, more and more researches support that E-cadherin plays an important role in the differentiation, growth and invasion of HGC. So it is of great value to clarify its mechanisms both for understanding HGC pathogenesis and for clinical therapy, especially in China, where there are a high risk population of gastric cancer and a high HGC incidence rate. In this paper, recent researches on CDH1 gene mutation, especially its role in tumor genesis and progress of HGC, are reviewed, and advances in evaluation of its mutation status for HGC diagnosis, therapy and prognosis, are also discussed briefly.