VIENNA — Cutaneous human papillomavirus infection may play a role in the development of skin cancer, Ingo Nindl, Ph.D., reported at the annual meeting of the European Society for Dermatological Research.
Infection by the same HPV variants was consistently detected in two of four patients with primary, recurrent, and metastatic nonmelanoma skin cancer, whose tumor biopsies were analyzed by polymerase chain reaction (PCR) for the presence of 24 cutaneous HPV types and their variants, according to Dr. Nindl of Charité Hospital in Berlin.
In one immunosuppressed patient, the primary squamous cell carcinoma and 8 of 10 recurrences that developed at sun-exposed sites after 4, 8, 9, 11, 37, 53, and 54 months of follow-up were consistently infected by the -E6 variants of HPV 21 and HPV 36.
In an immunocompetent patient, both the primary squamous cell carcinoma and a metastasis that developed after 8 months of follow-up were infected by HPV 14. Two others showed no consistent pattern of HPV infection in their primary and recurrent squamous cell carcinomas.
HPV's role in the development of genital cancers is well recognized. The first evidence that HPV might also be involved in nonmelanoma skin cancer came from studies of epidermodysplasia verruciformis, a rare disease in which patients present with extensive polymorphic warts that convert to squamous cell carcinoma in roughly 30%of cases, mostly involving sun-exposed sites.
The key carcinogenetic mechanism of HPV in epidermodysplasia verruciformis involves interference with the epidermal repair process by the HPV E6 protein, which inactivates UV induction of the proapoptotic protein BAK, resulting in a survival mechanism for HPV-infected keratinocytes. Whether the same mechanism figures in the development of nonmelanoma skin cancers in patients without epidermodysplasia verruciformis remains to be seen.