Ultrastructural localization of E-cadherin and alpha-/beta-catenin in adenoid cystic carcinoma

Aims: To investigate the disturbance of intercellular adhesion in adenoid c ystic carcinoma (ACC), we examined the ultrastructural localization of E-ca dherin (E-cad), alpha-catenin (alpha-cat) and beta-catenin (beta-cat) in AC C, and compared it with that in the normal labial gland. Methods and results: Using immune-electron microscopy, in the normal labial gland, E-cad was found to be uniformly distributed along the plasmalemma, where cells were in close contact with each other, with junctional complexe s, desmosomes and interdigitations; expression of alpha-cat and beta-cat wa s also detected. In ACC, which was classified into tubular, cribriform and trabecular types, E-cad expression seemed not to be uniform, but was observ ed to be along the plasmalemma where cell-to-cell contact was made. On the other hand, expression of alpha-cat or beta-cat was uneven in the trabecula r-type cells which were very slender and grew in an infiltrative scattered pattern into the extracellular matrix; that was absent in the cribriform-ty pe cells which made contact with each other mostly at the tip of the cytopl asmic processes. Conclusion: These findings suggest that the neoplastic cells of ACC express E-cad for use in intercellular adhesion, but the cadherin-catenin complex might not operate properly, which is the cause of neoplastic cell dissociat ion, followed by invasion and metastasis.