Expression of e-cadherin and alpha-catenin molecules in human breast-cancer tissues and association with clinicopathological features.

E-cadherin is a transmembrane glycoprotein that is regulated by its associated proteins, including alpha-catenin. To understand intercellular adhesion of cancerous tissues more precisely, we investigated E-cadherin and alpha-catenin expression in 87 human breast cancers immunohistochemically. All of the normal mammary glands consistently showed strong alpha-catenin expression on cell-cell boundaries. In contrast, various expression patterns were observed in cancerous tissues; 22 (25%) evaluated as uniformly positive, 32 (37%) as heterogeneous and 33 (38%) as uniformly negative. We found significant correlations between reduction in alpha-catenin expression and clinicopathological features, especially tumor invasion and metastasis. Furthermore, a significant correlation was found between E-cadherin and alpha-catenin expressions. These results suggest that E-cadherin mediated adhesion system may be affected by reduction in alpha-catenin expression and that alpha-catenin may play an important role in cancer invasion and metastasis.