p16 immunostaining as a predictor of anal and cervical dysplasia in women attending a sexually transmitted infection clinic

BACKGROUND: Carcinogenesis caused by human papillomavirus (HPV) leads to over-expression of p16 protein. p16 may act as a marker of HPV integration with host genome and serve as a surrogate marker of HPV oncogenesis. MATERIALS AND METHODS: A single center study of 75 women (35 HIV-positive and 40 HIV-negative women) was conducted. Anal and cervical specimens were obtained for cytology and p16 immunostaining. RESULTS: The sensitivity of p16 to diagnose anal and cervical dysplasia was 50% and 58.8%, respectively, whereas specificity was 98.6% and 100%, respectively. Positive predictive value for anal and cervical was 75% and 100%, whereas negative predictive value was 95.8% and 89.2%, respectively. A strong relationship between the grade of dysplasia and intensity of p16 immunoscore was observed (Pearson correlation r = 0.666, P < 0.0001 and r = 0.496, P < 0.0001 for anal and cervical, respectively). CONCLUSION: p16 immunostaining with greater specificity for high-grade lesions may improve the diagnostic accuracy, especially for high-grade lesions which have a high risk of progression to malignancy and thereby necessitate treatment.