Abstract: Objective To evaluate the role of E-cadherin (E-cad) and CDH1 gene encoding E-cad in the occurrence of sporadic or
hereditary gastric cancer. Methods Nineteen normal gastric mucosal issue specimens, 19 specimens of hereditary gastric
cancer (diagnosed according to ICG-HGC criteria), and 19 specimens of sporadic gastric cancer examined for E-cad expression
and CDH1 promoter methylation using immunohistochemistry and methylation-specific PCR (MSP). Results The protein
expression of E-cad were significantly reduced in both of the cancer tissues (P<0.001) compared with that in the normal gastric
mucosal tissues, and showed no significant difference between the two cancers (P=0.84). CDH1 promoter hypermethylation
was found in 10 out of the 19 hereditary gastric cancer tissues, a rate significantly higher than that in sporadic gastric cancer
tissues (3/19, P<0.01). Conclusion CDH1 promoter hypermethylation is probably an important factor contributing to reduced
E-cad expression in sporadic gastric cancer but not in hereditary gastric cancer.