Detection of human papillomaviruses in paired healthy skin and actinic keratosis by next generation sequencing

Actinic keratosis (AK) arises on photo-damaged skin and is considered to be the precursor lesion of cutaneous squamous cell carcinoma (cSCC). Many findings support the involvement of β human papillomaviruses (HPVs) in cSCC, while very little is known on γ HPV types. The objective of this study was to characterize the spectrum of PV types in healthy skin (HS) and AK samples of the same immunocompetent individuals using next-generation sequencing (NGS). Viral DNA of 244 AK and 242 HS specimens were amplified by PCR using two different sets of primers (FAP59/64 and FAPM1). Purified amplicons were pooled and sequenced using NGS. The study resulted in the identification of a large number of known β and γ PV types. In addition, 27 putative novel β and 16 γ and 4 unclassified PVs were isolated. Only HPV types of species γ-1 (e.g. HPV4) appeared to be strongly enriched in AK versus HS. The NGS analysis revealed that a large spectrum of known and novel PVs is present in HS and AK. The evidence that species γ-1 HPV types appear to be enriched in AK in comparison to HS warrants further biological and epidemiological studies to evaluate their role in the development of skin (pre)cancerous lesions.