Detection of human papillomavirus type 56 in Bowen's disease involving the nail matrix.

Background: As Bowen's disease of the nail apparatus is quite rare, there have been only a few reports on the prevalence of human papillomavirus (HPV) infection in this condition.
Objectives: The purpose of this study was to clarify the association of HPV with this disease involving the nail apparatus.
Methods: Five patients with Bowen's disease of the nail apparatus were investigated clinically, virologically and histologically. Total DNAs extracted from excised skin lesions were analysed using polymerase chain reaction (PCR) for the presence of HPV DNA and the amplified products were subjected to DNA sequence analyses. Histological localization of HPV DNA was examined by in situ hybridization.
Results: In three of five patients, HPV was detected by PCR amplification, and subsequent sequence analyses of the PCR products showed the sequences of HPV type 56. A common clinical feature of the three HPV-positive patients was longitudinal melanonychia. In contrast, the two HPV-negative patients presented with a convex nail deformity and a periungual ulcerative lesion. In two of three positive cases, there was a silent point mutation in the L1 gene of each HPV. In the remaining one case, the nucleotide sequence was consistent with the consensus sequence of HPV 56. Sequence analyses of the E6 gene revealed the infection of different variants of HPV 56 among the three cases. The viral genomes were located in keratinocyte nuclei upon in situ hybridization.
Conclusions: HPV 56 may be involved in the carcinogenesis of Bowen's disease affecting the nail matrix with longitudinal pigmentation.