An Immunohistochemical Study on Expression of β-catenin in Oral Squamous Cell Carcinomas - Comparative Analysis

Background: β-catenin is a versatile protein that contributes to cell–cell adhesion and also acts in the regulation of gene expression. Dysregulation of the Wnt/β-catenin signaling pathway has been reported across various human malignancies.

Objective: This study aimed to assess the β-catenin expression in different grades of OSCC by assessing its qualitative and semi-quantitative immunohistochemical expression in comparison to normal oral epithelium.

Materials and Methods: A comparative immunohistochemical study was carried out on 45 tissue specimens,  comprising two groups: Group A -30 cases of Oral Squamous Cell Carcinoma and Group B -15 samples of normal healthy oral mucosa serving as controls.  Tissue sections were stained with haematoxylin and eosin to confirm the histopathological diagnosis of both cases and controls, followed by immunohistochemical staining for β-catenin expression. The stained sections were independently evaluated by two blinded observers using a trinocular research microscope. Assessment of β-catenin expression was performed based on its subcellular localization, including membranous, cytoplasmic, and nuclear compartments. A semi-quantitative immunoreactivity score (IRS) was calculated by considering the proportion of positive cells and staining intensity for each compartment and the observations were statistically analysed.

Results: β-catenin expression in normal mucosal epithelium exhibited predominantly membranous expression, whereas OSCC, with increasing histopathological grade, there was a progressive shift from membranous to cytoplasmic and nuclear localization, with poorly differentiated OSCC showing maximum nuclear accumulation and the difference in expression of β-catenin was statistically significant  (p < 0.001).

Conclusion: The study concluded that β-catenin undergoes a redistribution from membrane-bound expression to cytoplasmic and nuclear localization during malignant transformation in OSCC. This shift reflects loss of cell adhesion and activation of oncogenic Wnt/β-catenin signaling. Therefore, β-catenin has  potential to serve as a diagnostic biomarker and may help in assessing tumor progression and aggressiveness.