PP105: Prevalence of human papillomavirus infection in oral lichen planus in Japanese patients

Purpose Oral lichen planus (OLP) is potentially premalignant disorder in which human papillomavirus (HPV) DNA is detected more often than in normal oral mucosa, but there is no firm evidence on HPV as a causative factor of oral cancer as yet. We assessed HPV-genotype distribution in OLPs of Japanese patients. Material and method We did research on HPV DNA in 200 cases OLP (77 males: average age 55.7 years and 123 females: average age 58.5 years) and extracted DNA from the formalin fixation paraffin-embedded samples. HPV DNA was detected by nested PCR using MY09/MY11 as external primers and GP5 + /GP6 + as internal primers targeting the L1 open reading frame of the HPV genome. HPV genotype was determined by type-specific PCR and direct DNA sequencing analysis. Result The positive rate of males and females were 37.7% and 47.2%, respectively. Frequent HPV types in the specimens of all OLPs were HPV-16 (36.0%), 18 (32.0%), 11 (13.0%), 6 (9.0%) and 33 (7.5%). Conclusion The results of the present investigation indicate that many HPVs, including the high risk (HPV 16, 18 and 33) and the low risk (HPV 6 and 11) were present in the OLP. It is suggested, therefore, that HPV infection is one of the risk factor of malignant transformation in OLP lesions. We are going to assess the potential role of HPV in a subset of OLP and in lesions that progress to SCC by further study.