Changes of E-cadherin and beta-catenin in human and mouse intestinal tumours.

An immunohistochemical analysis of E-cadherin and beta-catenin was performed in human colorectal cancer as well as in surrounding normal intestinal tissue. We also analysed the expression of these two cell adhesion proteins in transgenic Apc1638N mice as a model of human familial adenometous polyposis syndrome. In the normal intestinal mucosa of both species, E-cadherin and beta-catenin were localized along the lateral plasma membranes of epithelial cells. In intestinal tumour cells, however, they were also present in the cytoplasm. The expression of both proteins was reduced in human and mouse tumours. The pattern of their distribution was frequently heterogenous with strongly positive cells in a mosaic of negative ones. Further, E-cadherin and beta-catenin expression did not correlate to the Duke's staging of tumours and therefore neither can be used as prognostic criteria.