Human papillomavirus DNA in oral squamous cell carcinomas and normal mucosa

Human papillomavirus (HPV) infections in oral carcinomas and normal oral mucosa were studied by consensus primer screening and typing for HPV types 6/11, 16 and 18 DNA. After polymerase chain reaction (PCR) the DNA species of interest were identified by Southern blot hybridization with digoxigenin-labeled oligonucleotide probes. Frozen tissue and scrapings were equally suitable for HPV testing and yielded high HPV detection rates in carcinomas. By comparison, HPV analysis of paraffin-embedded material was much less efficient. HPV were demonstrated in 61.5% (16/26) of oral squamous cell carcinomas, high risk HPV 16 and 18 being the preferential types. The frequency of HPV detection in non-neoplastic mucosa of tumor patients decreased clearly with increasing distance from the tumor (range 26.9-3.8%) suggesting focal HPV infections. In contrast, normal buccal mucosa of a group of healthy volunteers contained HPV DNA only in 1% (1/97).