beta- and gamma-catenin expression in oral dysplasia

Cell-cell and cell-matrix interactions regulate important cellular functions; they involve a number of specialised molecules and the corresponding receptors, among which a key role is played by cadherins and the associated catenins. Deregulation of these molecules has been associated with tumour progression in many human malignancies. While catenins expression has been extensively studied in many human cancers, including oral carcinoma (OSCC), less is known about their expression in oral epithelial dysplasia. The objective of this study was to evaluate the expression of these proteins in a large group of displastic lesions of the oral mucosa and their relation with subsequent malignant transformation. Expression of beta- and gamma-catenin was investigated by immunohistochemistry using specific monoclonal antibodies in 49 cases of oral epithelial dysplasia and 10 samples of normal oral mucosa. The presence and absence of beta- and gamma-catenin staining was expressed differently in relation to dysplasia grade; while the degree of dysplasia became more severe, we observed a statistically significant loss and/or reduction of catenins expression, the loss of the exclusive membranous expression and a cytoplasmic delocalisation. Progression to OSCC occurred in 10 out of our 49 cases (20.4%); all of them, except one, showed a concurrent and concordantly located beta- and gamma-catenin staining even, if no statistically significant differences were found between cases progressed to invasive OSCC or not. Catenins physiology alterations may be involved in the transformation process; however, the role of catenins expression as possible prognostic markers in precancerous oral lesions seems to be limited. Nonetheless, further studies on larger series of samples are necessary in order to clarify the role of catenins expression in oral carcinogenesis from both a biological and clinical point of view.