Exposure profiles and human papillomavirus infection in skin cancer: an analysis of 25 genus beta-types in a population-based study.

An increasing number of studies report that genus beta human papillomaviruses (HPVs) are associated with skin cancer, with suggestions of specificity for squamous cell carcinoma (SCC) of the skin. We have conducted a systematic examination of HPV DNA in tumors from immunocompetent hosts, including SCC and basal cell carcinoma (BCC), using a highly sensitive methodology and population-based samples to test the hypothesis that a differential prevalence of beta-HPVs exists between SCC (n=101) and BCC (n=101) tumors. When testing for all known beta-HPV types, we found no significant difference in HPV prevalence between the two histologies. However, SCC lesions were significantly more likely to be infected with HPV genus beta-species 1 (includes types 5 and 8), than BCC samples (P=0.01); this difference was not observed for any other species. A histologic difference was also observed for those HPV types previously reported to be important in skin cancer (P=0.003). SCC samples showed a higher rate of infectivity (that is, were positive for multiple types) than BCC tumors (P=0.02). These data highlight the potential importance of various genus beta-HPV types, in particular genus beta-species 1 in SCC, and support the hypothesis of a behavioral difference of the virus within the two major histological skin cancers.