BCL-2 protein expression in oral squamous cell carcinoma and associated clinicopathological features as seen at the Pathology Department, Makerere University

Abstract

Background: Predicting clinical behavior of oral squamous cell carcinoma based on histopathological analysis requires immunohistochemical supplementation with biomarkers like Bcl-2 protein that can be used in prognostic assessment and management of OSCC. Objective: The aim of this study was to determine Bcl-2 protein expression in oral squamous cell carcinoma and its association with clinicopathological features as seen at the Pathology Department, Makerere University. Methods: A retrospective cross-sectional descriptive laboratory-based study conducted at the Pathology Department, Makerere University. One hundred four cases of OSCC were included in the current study. Hematoxylin and Eosin was done for histological confirmation and Bcl-2 protein mouse monoclonal antibody (anti-Bcl-2 clone 124, Dako) for IHC evaluation. Data was entered and analysed using STATA version 14.0 (Stata corp) software package and bivariate and multivariate analyses were performed. Chi-square test and adjusted odds ratio with a 95% confidence interval were used to determine the association between Bcl-2 protein expression and the independent variables (age, sex, topographical sites, histological subtype and histological grade) in OSCC. A p-value of ≤ 0.05 was considered statistically significant. Results: The prevalence of Bcl-2 protein expression was 29.8%. Bcl-2 protein expression was associated with sex where the male sex was an independent predictor of its expression (aOR = 4.76, 95% CI {1.22 – 18.60}, p = 0.025). In addition, Bcl-2 protein expression was also associated with basaloid histological subtype of OSCC which was also an independent predictor of its expression (aOR = 38.77, 95% CI {3.53 – 425.85}, p = 0.003). Majority of OSCC (58.7%) were well differentiated of which 24.6% stained positive for Bcl-2 protein expression. Moderately differentiated tumors constituted 28.9% and 40% stained positive for Bcl-2 protein expression while poorly differentiated tumors contributed 12.5% and 30.8% stained positive for Bcl-2 protein expression. Bcl-2 protein was also expressed more in OSCC that arose from the palate than those from other sites. However, no statistically significant association was found between Bcl-2 protein expression and histological grade, topographical sites as well as patient’s age in OSCC. Conclusion: Bcl-2 protein expression is associated with the male sex and poor prognostic histological subtype - basaloid squamous cell carcinoma. There is no association between Bcl2 protein expression and histological grade, topographical sites or age in OSCC.