Identification of genital tract papillomaviruses HPV‐6 and HPV‐16 in warts of the oral cavity

Warty lesions of the oral cavity were examined for etiologic association with genital tract papillomaviruses HPV‐6, HPV‐11, and HPV‐16. DNAs extracted from ten oral biopsies were screened for HPV genomic sequences by Southern transfer hybridization with ³²P‐labeled viral DNA probes. Nonstringent hybridization with an HPV‐6 probe revealed papillomavirus DNA sequences in four of seven tissues with histologic evidence of papillomatosis, in none of two tissues without histologic evidence of papillomatosis, and in one tissue that was not examined by histology. Stringent hybridization tests with HPV‐6 and HPV‐16 probes identified the genome in one tissue as being HPV‐16, in a second tissue as being HPV‐6 subtype a, and in a third tissue as HPV‐6 (subtype unidentified); papillomavirus DNA sequences in two tissues are as yet not identified. An additional case of HPV‐6 or HPV‐11 related oral cavity lesion was diagnosed by in situ hybridization of paraffin sections with a ³⁵S‐labeled, mixed HPV‐6 + HPV‐11 probe. The hybridization in the positive section was extensive and confined to epithelial nuclei. The oral lesions associated with genital tract papillomaviruses were asymptomatic, multiple or single, and were located in different parts of the oral cavity, for example, on the gingivae, on the tongue, on the lip, on the tonsillar pillar, and on the floor of the mouth.