Detection of HPV-2 and identification of novel mutations by whole genome sequencing from biopsies of two patients with multiple cutaneous horns

Abstract Background Human papillomavirus-2 (HPV-2) is generally associated with common warts. The association of cutaneous horns with HPV-2 infection has never been reported. Objectives To identify the papillomavirus (PV) type(s) involved in cutaneoue horns and analysis the genomes of these viruses. Study design We screened biopsies from two patients with multiple cutaneous horns using PV type-specific PCR assays, and sequenced the whole genomes of the viruses by a PCR-by-PCR strategy. Sequence comparison with the reference genome and its closely related PVs in the same phylogenetic group was performed to identify sequence variation across the genome(s) of newly detected PV(s). Results Two strains of HPV-2 were identified from the biopsies of two patients respectively. No double or multiple infections were detected. Novel mutations were found in the HPV-2 genome, located both in the coding and non-coding regions. Amino acid changes occurred only in E1 and E7 ORFs. The two strains also shared several mutations at the same positions. Conclusions Each patient was infected with a single strain of HPV-2 that developed unique mutations; HPV-2 may play a role in the onset and development of cutaneous horns; amino acid changes in functionally significant viral proteins may confer differential pathogenic risks.