p16INK4a as a Biomarker in Cervical Precancerous and Cancerous Lesions: An Immunohistochemical Cross-Sectional Analysis

Background: p16INK4a is a cyclin-dependent kinase inhibitor overexpressed in high-risk HPV-associated cervical lesions. Objective: To assess p16INK4a expression across cervical lesion grades and correlate with histopathological parameters. Methods: This cross-sectional study analysed 98 cervical biopsies (LSIL, HSIL, carcinoma). Immunohistochemistry for p16INK4a was performed. Expression intensity and extent were scored (0-3+). Statistical correlations with lesion grade, pleomorphism, and mitotic activity were evaluated. Results: Strong p16INK4a expression was found in 84.6% of HSIL and all carcinoma cases, but only 21.4% of LSIL. p16 positivity correlated significantly with nuclear pleomorphism and mitotic activity (p < 0.001). ROC analysis (AUC = 1.00) demonstrated excellent diagnostic accuracy. Conclusion: p16INK4a expression correlates with cervical lesion severity and histological atypia, confirming its diagnostic utility in differentiating high-grade lesions, especially in low-resource settings.