Changes in the E-cadherin-catenin complex expression in early and advanced gastric cancers

In various human cancers, dysfunction of the E-cadherin-catenin complex is associated with a decrease in cellular and tissue differentiation and with higher invasive and metastatic potentials. Since advanced gastric cancers are thought to evolve from early gastric cancers, we investigated whether differences of the E-cadherin-catenin complex expression can be observed between early and advanced gastric cancers.

We have used an immunohistochemical technique to localize E-cadherin and alpha-, beta-, and gamma-catenins in 114 formalin-fixed, paraffin-embedded tissue blocks: 57 from patients with early gastric cancer and 57 from patients with advanced gastric cancer.

The immunoreactivity of E-cadherin and alpha-, beta-, and gamma-catenins was expressed by normal gastric epithelial cells with strong membranous staining at the intercellular border. Reduced expression of E-cadherin and alpha-, beta-, and gamma-catenins occurred in a considerable proportion of both cancer groups. However, no significant difference was seen between early and advanced cancer groups. In the early cancer group, reduced expression of E-cadherin and alpha-, beta-, and gamma-catenins correlated with diffuse type of cancer and poor differentiation. However, in the advanced cancer group, reduced expression of the three adhesion molecules, but not beta-catenin, correlated with diffuse type of cancer and poor differentiation. The expression of E-cadherin and alpha-, beta-, and gamma-catenins did not correlate with depth of invasion or lymph node metastases in both cancer groups.

These results suggest that alterations of the E-cadherin-catenin complex may be induced at an early stage of gastric tumorigenesis and may be associated with poorly differentiated and diffuse-type pathways in gastric tumorigenesis.