1. ^*Laboratory for Toxicology, Pathology, and Genetics, National Institute of Public Health and the Environment (RIVM), Bilthoven, The Netherlands
2. ^†Department of Medical Microbiology, Center of Infectious Diseases, Leiden University Medical Center, Leiden, The Netherlands
3. ^‡Department of Dermatology, Leiden University Medical Center, Leiden, The Netherlands
4. ^§Department of Health Risk Analysis and Toxicology, University of Maastricht, The Netherlands

Correspondence: Henk van Loveren, Laboratory for Toxicology, Pathology, and Genetics, National Institute of Public Health and the Environment (RIVM), PO Box 1, 3720 BA Bilthoven, The Netherlands. Email: h.van.loveren@rivm.nl

Received 20 August 2003; Revised 6 November 2003; Accepted 4 December 2003.

Abstract

Ultraviolet radiation (UVR) is associated with an increased risk of squamous cell carcinoma (SCC), which is in part due to immunomodulation. In addition, human papilloma virus (HPV), especially the epidermodysplasia verruciformis (EV)-associated types, may be involved. In view of the capacity of UVR to impair host resistance to infections, we investigated the relationship between solar exposure and the prevalence of cutaneous HPV. In a case-control study on skin cancer (320 controls and 156 patients) a lifetime-retrospective questionnaire on sun exposure was administered. The presence of DNA of HPV types 5, 8, 15, 20, 24, and 38 in plucked eyebrow hair and type-specific seroreactivity were assessed and analyzed in relation to estimated exposure. Sunburn episodes in the past, especially at age 13–20 y, appeared to be associated with an enhanced risk of EV–HPV DNA positivity. In contrast, a higher lifetime sun exposure was associated with a lower risk of HPV infection. These results indicate that UVR at erythematogenic doses increases the risk of EV–HPV infection, possibly due to impaired host resistance to HPV and/or a direct effect of UVR on viral replication. The favorable association between lifetime sun exposure and HPV prevalence, however, underscores the enigmatic role of HPV in skin carcinogenesis.