Human papillomavirus type 16 DNA in periungual squamous cell carcinomas.

Ten squamous cell carcinomas (in situ or invasive) of the fingernail region were analyzed for the presence of DNA sequences homologous to human papillomavirus (HPV) by dot blot hybridization. In most patients, the lesions were verrucae of long-term duration that were refractory to conventional treatment methods. Eight of the lesions contained HPV DNA sequences, and in six of these the sequences were related to HPV 16 as deduced from low-stringency nucleic acid hybridization followed by low- and high-stringency washes. Furthermore, the restriction endonuclease digestion pattern of DNA isolated from four of these lesions was diagnostic of episomal HPV 16. The high-frequency association of HPV 16 with periungual squamous cell carcinoma is similar to that reported for HPV 16 with squamous cell carcinomas on mucous membranes at other sites, notably the genital tract. Our findings suggest that HPV 16 may play an important role in the development of squamous cell carcinomas of the finger, most notably those lesions that are chronic and located in the periungual area.