Predictive Contribution of p16 Beyond HPV Genotype in the Histopathologic Detection of CIN2+ Lesions: A Real-World Cervical Biopsy Cohort Study.

Background: HPV genotype-based stratification estimates cervical disease risk but does not directly measure cellular transformation. We assessed whether p16 and Ki-67 improve prediction of CIN2+ beyond HPV genotype and age in a biopsy-confirmed referral cohort. Methods: This retrospective study included 531 high-risk HPV-positive women evaluated between December 2023 and January 2026 who had either margin-negative excisional histopathology or completed 12-month surveillance after conservative management. HPV genotypes were grouped as HPV16, HPV18, or other high-risk types. Independent associations were examined using prespecified multivariable logistic models; discrimination, calibration, 2000-resample bootstrap validation, and a uniform index-biopsy-reference sensitivity analysis were evaluated. Results: CIN2+ was confirmed in 191/531 women (36.0%). HPV16 positivity (adjusted odds ratio [aOR] 1.72, 95% confidence interval [CI] 1.15-2.57), age (aOR 1.027 per year, 95% CI 1.011-1.043), and p16 positivity (aOR 2.97, 95% CI 1.81-4.89) independently predicted CIN2+, whereas Ki-67 did not (aOR 1.74, 95% CI 0.90-3.35; p = 0.098). Adding p16 to age and genotype increased the AUC from 0.608 to 0.704 (ΔAUC 0.097, bootstrap 95% CI 0.057-0.138); Ki-67 increased it only to 0.707 (ΔAUC 0.003, 95% CI -0.002 to 0.015). Optimism-corrected AUCs were 0.599, 0.696, and 0.697, respectively. The uniform biopsy-reference analysis produced the same pattern. Conclusions: p16 provides reproducible incremental risk information beyond age and HPV genotype in biopsy-confirmed cervical disease, whereas Ki-67 adds little once p16 is known. Neither biomarker should replace histopathology-guided management.