To Örebro University

Background: Penile squamous cel carcinoma (pSCC) cancer has been considered a rare tumour in the western world. Although some conflicting results, the most recent meta-analyses report an increase in its incidence and in the percentage of HPV(+) cases in numerous western countries. This scenario mirrors what observed for HPV(+) oropharynx cancer and could be explained by changes in sexual practice and in exposure of men to HPV. In this study, we analyzed pathological features and HPV-DNA prevalence in a contemporary, western pSCC cohort.

Design: This study enrolled 206 patients with pSCC from Örebro University. DNA was extracted from paraffin-embedded tumor tissue samples, and HPV-DNA genotyping were performed using PCR method Anyplex II HPV28. In a subset of cases, HPV-DNA was also assessed in penile intraepithelial neoplasia (PeIN), lymph node metastasis (LnM) or both (51%, 11.6% and 18.9%). All the cases have been histologically re-classified according to the WHO 2016 classification of pSCC.

Results: HPV -DNA was detected in 92/206 (44.7%) pSCC, 78/141 (55.3%) PeIN and 28/61 LnM (45.9%), respectively. HPV16 was the predominant type, representing 78.3% for pSCC, 79.5% for PeIN and 96.4% for LnM. In 7.8% of the cases, more than a HPV genotype has been detected in the same specimen or in different specimens of the same patients. Curiously, we found 8.5% of cases (14/164) with discordance of HPV-DNA detection in different specimens from the same patient (pSCC, PeIN and/or /LnM). In HPV(+) pSCC the predominant histologic subtype was “warty” (41.3%); in HPV(-) pSCC it was “usual” (65.8%). For PeIN, “warty” was the predominant subtype in HPV(+) PeIN (39.7%) and “differentiated” in HPV(-) PeIN (79.4%). For pSCC, we observed disagreement between histology and HPV status in 23.8% of cases: 13.1% HPV(+)/Non-HPV -related histology and 10.7% HPV(-)/HPV-related histology.

Conclusions: HPV -DNA was observed in a relevant portion of pSCC and PeIN in our case series, confirming an increasing role of HPV in the pathogenesis of this disease. These results are particularly relevant, as they reflect the current epidemiological trend in the western world. Future studies are needed to clarify the exact role of HPV in cases with discordance between histology and HPV status and in cases with disagreement of HPV detection in different specimens from the same patient (pSCC, PeIN and/or LnM).