Detection of human papillomavirus DNA in oral verrucous carcinoma by polymerase chain reaction

Archival tissue biopsies of 17 cases of oral verrucous carcinoma were tested for human papillomaviruses by polymerase chain reaction followed by DNA slot-blot hybridization. Sections of the biopsies were also tested by in situ DNA hybridization with biotin-labeled probes for human papillomavirus types 6/11, 6/18, and 31/33/35. Using polymerase chain reaction, human papillomavirus DNA was detected in seven of 17 cases (41%). Slot-blot hybridization of the amplification products identified human papillomavirus type 6 in two cases, type 11 in four cases, and both types 6 and 11 in one case of oral verrucous carcinoma. In situ hybridization confirmed the presence of human papillomavirus type 6/11 DNA in tumor cell nuclei for each of the cases which tested positive by polymerase chain reaction and was negative in the remaining 10 cases. We conclude that human papillomavirus types 6 and 11 are frequently present in cases of oral verrucous carcinoma.