Human papillomavirus, Epstein-Barr virus, and methylation status of p16ink4a in penile cancer.

Little is known about penile carcinogenesis. The aim of this study was to evaluate the prevalence of HPV and EBV, and the methylation status of p16ink4a in penile cancer samples, and to contribute to the understanding of the mechanisms responsible for penile cancer development. HPV DNA was detected in 63.6% of 122 cases, with HPV16 being the most prevalent type. EBV DNA was detected in 47.7%, with EBV-1 being the most prevalent type. HPV/EBV co-infections were found in 27.3% of the cases. Hypermethylation in p16ink4a was detected in 64.5% of 110 tested cases. An association between the absence of HPV absence and p16ink4a hypermethylation was also found. Death and/or progressive disease was associated with grade (P = 0.001), T stage (P < 0.0001), and N stage (P < 0.0001). In the multivariable model, grade and N stage were independent risk factors for disease-free survival (P = 0.008 and P < 0.001, respectively). Patients without viral infection had a median age significantly lower than that of the HPV-infected patients. We suggest at least two pathways for penile carcinogenesis, one HPV-independent linked to epigenetic events, probably via p16ink4a inactivation; and another, dependent on HPV infection.