Increased nuclear beta-catenin expression in oral potentially malignant lesions: A marker of epithelial dysplasia.

BACKGROUND: Deregulation of beta-catenin is associated with malignant transformation; however, its relationship with potentially malignant and malignant oral processes is not fully understood. The aim of this study was to determine and compare the nuclear beta-catenin expression in oral dysplasia and oral squamous cell carcinoma (OSCC). MATERIAL AND METHODS: Cross sectional study. Immunodetection of beta-catenin was performed on 72 samples, with the following distribution: 21 mild dysplasia, 12 moderate dysplasia, severe dysplasia 3, 36 OSCC including 19 well differentiated, 15 moderately differentiated and 2 poorly differentiated. Through microscopic observation the number of positive cells per 1000 epithelial cells was counted. For the statistical analysis, the Kruskal Wallis test was used. RESULTS: Nuclear expression of beta-catenin was observed in all samples with severe and moderate dysplasia, with a median of 267.5, in comparison to mild dysplasia whose median was 103.75. Only 10 samples (27.7%) with OSCC showed nuclear expression, with statistically significant differences between groups (p < 0.05). CONCLUSIONS: Our results are consistent with most of the reports which show increased presence of beta-catenin in severe and moderate dysplasia compared to mild dysplasia; however the expression of nuclear beta-catenin decreased after starting the invasive neoplastic process. This suggests a role for this protein in the progression of dysplasia and early malignant transformation to OSCC. Immunodetection of beta-catenin could be a possible immune marker in the detection of oral dysplasia.