CDH1 and gastric cancer: E-cadherin encoded by gene CDH1 has genetic and epigenetic abnormalities in both germline and sporadic gastric cancer, mainly including gene expression level changes, germline and somatic mutations, 16q22.1 allele deletion, promoter methylation andnoncoding RNA (noncoding RNA, ncRNAs) regulated epigenetic gene silencing, etc., leading to abnormal expression of E-cadherin.