Increased risk of skin cancer associated with the presence of epidermodysplasia verruciformis human papillomavirus types in normal skin.

BACKGROUND: Human papillomaviruses (HPVs) are found in normal skin and in benign and malignant skin conditions. Epidermodysplasia verruciformis (EV) HPV types are those most plausibly linked to the development of squamous cell carcinomas of the skin.
OBJECTIVES: To assess the risk of nonmelanoma skin cancer (NMSC) associated with the presence of EV HPV in normal skin in immunocompetent (IC) individuals and renal transplant recipients (RTRs).
METHODS: Using a degenerate and nested polymerase chain reaction technique, HPV DNA was sought in 124 normal skin samples from sun-exposed and nonsun-exposed sites, from 39 IC individuals and 38 RTRs, both with and without NMSC. Data were analysed using the Mantel-Haenszel test and by logistic regression analysis.
RESULTS: HPV DNA was detected in 58/67 (87%) and 20/57 (35%) samples from renal transplant and IC patients, respectively. There was no difference in either the prevalence or spectrum of HPV types found in sun-exposed and nonsun-exposed normal skin. However, there was significant association between NMSC and the presence of EV HPV DNA. Multivariate analysis provided an odds ratio of 6.41 (95% confidence interval 1.79-22.9) for the association of EV HPV DNA in normal skin (irrespective of site) and NMSC status, even after stratifying for patient group and adjusting for the clustering effect of multiple sampling. Conversely, there was no association between skin cancer status and the presence of cutaneous or mucosal HPV types in either sun-exposed or nonsun-exposed skin.
CONCLUSIONS: HPV DNA is widespread in normal adult skin, particularly in transplant patients. In our study, the presence of EV but not cutaneous HPV DNA in normal skin was significantly associated with NMSC status and may prove to be of predictive value for skin cancer risk. These data provide reason to focus on EV HPV types as causal agents in skin cancer.