To investigate the mechanisms of disruption of cell-cell contact in scirrhous carcinoma cells, the expression of both E-cadherin and alpha catenin, which is an intracellular cadherin-binding molecule, were determined in scirrhous-type adenocarcinomas of the stomach and breast using immunohistochemical and immunoblotting techniques. The losses of E-cadherin expression in gastric and breast scirrhous adenocarcinomas were 18.1% and 0%, respectively, and those of alpha catenin expression were 54.6% and 75%, respectively. Frequent loss of alpha catenin expression occurred in scirrhous carcinomas with scattered cell growth in the stomach and the breast and showed no organ specificity. In addition, all the infiltrating lobular carcinomas, which also infiltrate the stroma as single cells, showed no E-cadherin or alpha catenin expression. These findings suggest that down-regulation of either alpha catenin or E-cadherin plays a critical role in the disruption of cell adhesion in carcinomas with scattered cell growth.