E cadherin gene deficiency is seen in -

The majority of gastric cancers are not hereditary, the mutations identified in familial gastric cancer have provided important insights into mechanism of carcinogenesis in sporadic cancers. Germline mutations in CDH1, which encodes E cadherin, a protein that contributes to epithelial intercellular adhesion are associated with familial gastric cancers, which are usually of diffuse type. Mutations in CDH1 are present in about 50% of sporadic cases of diffuse gastric cancers, while E cadherin expression is drastically decreased in the rest, often by methylation of the CDH1 promoter. Lobular carcinoma of breast which also tends to infiltrate as single cells, & individuals with BRCA2 mutations are at increased risk of developing diffuse gastric cancers.