Four novel human betapapillomaviruses of species 2 preferentially found in actinic keratosis

Recent studies have suggested an association between human papillomaviruses (HPVs), particularly species 2 members of the genus Betapapillomavirus, and squamous cell carcinoma (SCC) of the skin. As most of these viruses are uncharacterized, molecular characterization and epidemiology are needed to advance our understanding of their significance in carcinogenesis. This study determined the complete genomes of four betapapillomaviruses of species 2 from skin lesions designated HPV-107, -110 and -111 and FA75[KI88-03], an isolate of an unpublished HPV type, and analysed their prevalence and viral loads in biopsies from SCC, actinic keratosis (AK), basal cell carcinoma, seborrhoeic keratosis and the healthy skin of 263 immunocompetent patients by HPV type-specific real-time PCR assays. Seventeen patients (6.5 %) harboured at least one of the four HPV types in their lesion, whereas seven patients (2.7 %) harboured one or more of the HPV types in healthy skin. Overall, the four viruses were more common in AK than in healthy skin (odds ratio 5.0, 95 % confidence interval 1.4-17.5), but the prevalence and viral loads were low. This characterization of HPV-107, -110 and -111 and FA75[KI88-03] expands the heterogeneity of members of species 2 of the genus Betapapillomavirus. However, as these types were found in only a few samples and in low amounts, a possible role in carcinogenesis remains elusive.