Exposure Profiles and Human Papillomavirus Infection in Skin Cancer: An Analysis of 25 Genus β-Types in a Population-Based Study

An increasing number of studies report that genus β 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 β-HPVs exists between SCC (n=101) and BCC (n=101) tumors. When testing for all known β-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 β-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 β-HPV types, in particular genus β-species 1 in SCC, and support the hypothesis of a behavioral difference of the virus within the two major histological skin cancers.