Altered β-catenin expression in oral mucosal dysplasia: a comparative study

Objective: The current study aimed to investigate the beta-catenin expression in oral leukoplakia (OL) with different degrees of epithelial dysplasia and normal oral mucosa. Material and Methods: Formalin-fixed, paraffin-embedded tissue samples of 39 OL (mild dysplasia n=19, moderate dysplasia n=13, and severe dysplasia n=7), and 10 normal oral mucosa (control group) were submitted to immunohistochemical reactions to anti-beta-catenin primary antibody. A qualitative beta-catenin analysis was performed based on the percentage of positive cells. The cellular location and the epithelial layer were also considered. The Chi-square test and the Fishers exact test were used to verify possible differences in the beta-catenin expression among the OL groups. A p-value of <0.05 was considered statistically significant. Results: Membranous expression of beta-catenin in parabasal and basal layers was gradually lost in the higher degrees of epithelial dysplasia. In normal oral mucosa, beta-catenin was detected only in the cytoplasmic membrane. However, a significant increase in cytoplasmic beta-catenin could be observed between mild and moderate dysplasia (Fisher Exact test - p<0.001) and between mild and severe dysplasia (p<0.001). Conclusions: The beta-catenin cytoplasmic expression observed in this study may represent the initial stage of modifications in the E-cadherin-catenin complex, along with morphological cellular changes.