Human papillomavirus infection and immunohistochemical p16(INK4a) expression as predictors of outcome in penile squamous cell carcinomas

Approximately 50% of penile squamous cell carcinomas (SCC) are associated with high-risk human papillomavirus (HR-HPV) infection. We evaluated the correlation of p16(INK4a) expression and HR-HPV with clinicopathological features and outcome in a cohort of patients with penile SCC. Two tissue microarrays were constructed from 53 invasive penile SCC at our hospital. p16(INK4a) expression was assessed by immunohistochemistry (CINtec Kit). High-risk human papillomavirus status was assessed by in situ hybridization (INFORM HPV III family 16 probe B cocktail). High-risk human papillomavirus was detected in 8 cases (15%), and p16(INK4a) overexpression was found in 23 cases (44%). Both markers showed a significant association with histologic subtype (P = .017 and P = .01, respectively) and lymphovascular invasion (P = .015 and P = .015, respectively). Regarding outcome analyses, neither HPV infection nor p16(INK4a) overexpression significantly predicted overall survival or cancer-specific survival using Cox proportional hazards regression model. High-risk human papillomavirus positivity and p16(INK4a) overexpression were significantly associated with histologic subtype and presence of lymphovascular invasion. Human papillomavirus status was not predictive of outcome in our cohort.