Human papillomavirus 16 is an aetiological factor of scrotal cancer

Background: Squamous cell scrotal carcinoma (SCSC) is an infrequent skin cancer associated historically with occupational carcinogens. Human papillomavirus (HPV) DNA has been associated with SCSC but there is no definitive proof of its oncogenic role. Methods: Human papillomavirus-DNA and –E6*I mRNA were analysed in six invasive histologically typed SCSC. LCM-PCR was used to localise HPV DNA to tumour cells. P16 INK4a and p53 expression were studied by immunohistochemistry. Results: In three warty or basaloid SCSC HPV16-DNA and E6*I-mRNA were detected. LCM-PCR confirmed HPV16 was in p16 INK4a -positive malignant cells. However, of three usual-type SCSC, all were HPV-negative and two expressed p53 protein but not p16 INK4a . Conclusions: Human papillomavirus 16 was present in tumour cells and oncogenically active in basaloid and warty SCSC, whereas usual SCSC was HPV-negative and showed immunostaining, suggesting p53 mutation. The dual pathways of oncogenesis and relation between histological type of SCSC and HPV are similar to that in penile cancers.