Immunohistochemical evaluation of cellular retinol binding protein-1 expression across histological grades of oral squamous cell carcinoma: A retrospective analysis

Objective: To analyze the correlation between cellular retinol-binding protein-1 (CRBP-1) expression and tumor grade, differentiation, and invasiveness in oral squamous cell carcinoma. Methodology: This retrospective immunohistochemical study was conducted at Pathology Department of Mayo Hospital, Lahore, from January 2024 to May 2025 after ethical approval. A total of 30 formalin-fixed, paraffin-embedded oral squamous cell carcinoma (OSCC) tissue specimens were retrieved and graded histologically. An anti-CRBP-1 antibody was used for immunohistochemical staining. Expression levels were semi-quantitatively scored and correlated with tumor grade (well, moderately, and poorly differentiated). Results: Out of 30 OSCC cases, strong CRBP-1 positivity was observed in 14 cases (46.7%). Among these, 4 cases (28.6%) were well-differentiated, 8 cases (57.1%) were moderately differentiated, and 2 cases (14.3%) were poorly differentiated. Another 14 cases (46.7%) showed weak CRBP-1 expression, while 2 cases (6.7%) were negative. A statistically significant inverse correlation was found between CRBP-1 expression and tumor grade (Spearman’s p = –0.52; p < 0.01), indicating reduced expression in less differentiated tumors. Conclusion: CRBP-1 expression is inversely associated with histological grade in OSCC, suggesting its potential role as a differentiation marker and possible prognostic indicator.