High prevalence of epidermodysplasia verruciformis-associated human papillomavirus DNA in actinic keratoses of the immunocompetent population

Skin cancers in both immunosuppressed and immunocompetent populations are associated with epidermodysplasia verruciformis human papillomavirus (EV-HPV) DNA. However, little is known about the prevalence of EV-HPVs in actinic keratoses in immunocompetent individuals. Actinic keratoses from 114 patients were classified as low-grade (n=76) or high-grade (n=38) according to the extent of histological atypia. HPV DNA was amplified from 54 frozen and 60 paraffin-embedded biopsy specimens by nested polymerase chain reaction (PCR) with several consensus and type-specific primers. PCR products were sequenced for typing. These results were compared with HPV detection in skin cancers (n=20) and Bowen's disease (n=18). A broad spectrum of EV-HPV types including oncogenic HPV5 and HPV8 and partially characterized sequences were detected in actinic keratoses and cutaneous cancers. In actinic keratoses a higher prevalence of EV-HPV DNA was found in frozen tissues than in formalin-fixed tissues (85% vs 67%). There was no difference between the low- and high-grade actinic keratoses either in terms of EV-HPV DNA prevalence or the results of serological study using HPV8 virus-like particles. The detection rate of EV-HPVs was lower in skin cancers and Bowen's disease. This would suggest involvement of EV-HPVs in the early stages of cutaneous oncogenesis.