Detection of human papillomavirus type 16 in Bowen's carcinoma of the toe

Background Human papillomavirus (HPV) is known to cause cervical cancer. Because it has been detected in lesions of Bowenoid papulosis, Bowen’s disease, and Bowen’s carcinoma, HPV infection has been implicated in the pathogenesis of these diseases. Methods A 44‐year‐old man was diagnosed clinicopathologically with Bowen’s carcinoma of the right great toe. He developed multiple organ metastases and died. We examined HPV DNA in skin biopsy specimens from the primary and skin metastatic lesions by polymerase chain reaction (PCR) and in situ hybridization (ISH). The PCR assay was carried out using primer sets specifically designed for detecting the E6 and E7 genes of the HPV types associated with malignancy. Purified and cloned PCR products were subjected to DNA sequence analysis. The ISH studies used INFORM^® HPV III probes. Results We found HPV DNA in specimens from both the primary and the skin metastatic lesions. DNA sequencing detected HPV type 16. We compared the base sequences of viral DNA from the primary and metastatic lesions. Point mutations of the base sequences of the E6 and E7 genes were observed in viral DNA from metastases but not in that from primary lesions. The E6 gene had mutated from G to A in the 383rd base sequence, causing a Glu‐to‐Lys amino acid change. Results of ISH showed punctuate signals in the nuclei of tumor cells. Conclusions We suspect an association between HPV 16 infection and the development of this malignant occurrence.