Correlation of E-cadherin and alpha-catenin expression with differentiation of oral squamous cell carcinoma

The precise mechanism of disruption of cell-cell adhesion in oral squamous cell carcinomas has yet to be established. We therefore sought to clearly this mechanism by investigating expression of both E-cadherin (E-CD) and alpha-catenin (alpha-CAT), which is an intracellular CD-binding molecule, in squamous cell carcinomas of the tongue, gingiva and floor of the mouth using immunohistochemical and immunoblotting techniques. We found that reduced expression of both E-CD and alpha-CAT occurred more frequently in moderately- and poorly-differentiated carcinomas than in well-differentiated specimens (p < 0.001), and this reduced expression showed no regional specificity. Relatively frequent loss of alpha-CAT expression in poorly-differentiated carcinomas was detected by both immunohistochemical and immunoblotting analyses. These findings suggest that E-CD and alpha-CAT are both important regulators of intercellular adhesion, and that the reduction of these molecules is also linked to the process of tumor dedifferentiation.