Bcl-2 Protein Expression in Oral Squamous Cell Carcinoma and Associated Clinicopathological Features at a Tertiary Teaching Institution in Uganda

Abstract

Background: Oral squamous cell carcinoma (OSCC) is the most common malignancy of the oral cavity and a significant public health challenge in sub-Saharan Africa. Conventional histopathology often fails to predict clinical outcomes accurately, leading to a search for molecular biomarkers. The B-cell lymphoma 2 (Bcl-2) protein, an anti-apoptotic factor, is involved in cell survival and treatment resistance. This study determined the prevalence of Bcl-2 expression in OSCC and its association with clinicopathological features in Uganda. Methods: This cross-sectional laboratory study analyzed 104 archived formalin-fixed paraffin-embedded (FFPE) tissue blocks of OSCC cases from Makerere University (2010–2020). Histological subtyping and grading followed WHO (2017) criteria. Immunohistochemistry (IHC) was performed using the anti-Bcl-2 clone 124. Expression was scored semi-quantitatively (intensity + percentage of positive cells). Data were analyzed using Chi-square tests and multivariate logistic regression. Results: Bcl-2 was expressed in 29.8% (31/104) of OSCC cases, predominantly in a granular cytoplasmic pattern. In well-differentiated tumors, staining was most intense at the invasive periphery. Multivariate analysis identified male sex (aOR = 4.76, p = 0.025) and the basaloid histological subtype (aOR = 38.77, p = 0.003) as independent predictors of Bcl-2 expression. No significant associations were found with age, tumor site, or histological grade. Conclusion: Approximately 30% of OSCC cases in Uganda express Bcl-2, with significant associations noted for male patients and the aggressive basaloid subtype. These findings suggest Bcl-2 as a prognostic indicator and potential therapeutic target.