EXPRESSION OF E-CADHERIN, ALPHA-CATENINS AND BETA-CATENINS IN HUMAN GASTRIC CARCINOMAS - CORRELATION WITH HISTOLOGY AND TUMOR PROGRESSION

The expression of cell-cell adhesion molecule, E-cadherin and its asso ciated proteins, alpha- and beta-catenins in human gastric carcinomas was examined by Western blotting. All the seven gastric carcinoma cell lines expressed E-cadherin except KATOIII, which was derived from ple ural effusion of a scirrhous type stomach cancer or Borrmann's type-4 carcinoma. The expression of alpha-catenin was not detected in HSC43 d erived from scirrhous carcinoma, while HSC39 expressed abnormal beta-c atenin caused by genetic alteration. In gastric carcinoma cases, the l evels of E-cadherin and alpha-catenin were significantly lower in poor ly differentiated adenocarcinomas and scirrhous carcinomas when compar ed to other types of gastric carcinomas. Deeply invasive carcinomas ex pressed E-cadherin and alpha-catenin at lower levels. However, the exp ression level of alpha-catenin was not necessarily consistent with tha t of E-cadherin. One of 10 gastric carcinomas examined showed complete deletion of alpha-catenin gene in Southern blotting. beta-catenin was expressed at lower level in poorly differentiated adenocarcinomas tha n in well-differentiated adenocarcinomas. These findings suggest that reduction in the expression of E-cadherin and its associated molecules , catenins, is involved in the development and infiltrative growth of scirrhous type gastric carcinomas.