Human Papillomavirus Prevalence in Seminal Tract Among the Patients with Testicular Tumor; Dose HPV Infection Have an Etiological Role for the Development of Testicular Tumor?

This study investigated the prevalence, genotypes, and tissue localization of human papillomavirus (HPV)-DNA in testicular tumor including epididymis and spermatic cord specimens from 116 Japanese patients who underwent radical inguinal orchiectomy. Formalin-fixed, paraffin-embedded tissues were analyzed by nested polymerase chain reaction (PCR), followed by sequencing-based HPV genotyping. HPV-DNA localization was assessed by in situ hybridization (ISH), and E6/E7 mRNA ISH was performed in HPV-positive specimens. HPV-DNA was detected in three patients (3/116, 2.6%), including one testicular tumor specimen (1/116, 0.9%) and two spermatic cord specimens (2/116, 1.7%). All HPV-positive specimens contained HPV16-DNA. HPV-DNA ISH signals were observed in seminoma cells in one testicular specimen and in the vas deferens epithelium in one spermatic cord specimen. On the other hand, ISH signals were not present in epididymis tissue in the HPV-positive testicular tumor tissue, suggesting that HPV-DNA detection rate of epididymis was 0%. E6/E7 mRNA signals were not detected in any HPV-positive specimen. These findings demonstrate that HPV16-DNA was surely present in testicular tumor and the vas deferens epithelium. However we could not provide evidence of transcriptionally active HPV oncogenes, and could not establish a causal role in testicular tumorigenesis.