Human papillomavirus in oral atrophic lichen planus lesions.

OBJECTIVES: Oral lichen planus (OLP) is potentially premalignant disorder in which human papillomavirus (HPV) DNA is detected more often than in normal oral mucosa. We assessed HPV-genotype distribution in atrophic OLPs as related to DNA content and repair, proliferation activity, apoptosis, cell adhesion and lymphocyte infiltration.

MATERIALS AND METHODS: Eighty-two OLP patients (74.4% women) with a mean follow-up-time of 62.4 months were included in the study. HPV was genotyped with Luminex-based assay detecting 24 HPV-genotypes. Data on a panel of biomarkers and static cytometry performed in these samples before were compared with HPV data.

RESULTS: HPV DNA was found in 15.9% of OLPs with genotypes: HPV6/11/16/31/33 and one multiple-type infection. Two of the five patients who developed cancer had low-risk HPV6/11 infection while three were HPV-negative. There was a statistically significant correlation between HPV DNA in OLP and DNA content and ploidy markers determined with static cytometry: in HPV-positive samples, proliferation index was higher (p=0.016), less cells were in resting state G1/G0 (p=0.021) but more often in the S-phase (p=0.036) than in HPV-negative lesions. HPV positivity was also related to topoisomerase IIα (p=0.051), caspase-3 (p=0.049) and CD20 (p=0.010) protein expression.

CONCLUSION: HPV-infection is associated with a subgroup of atrophic OLP. Static cytometry is a sensitive method to identify HPV-associated changes in DNA content and cell proliferation. Of 16 markers, only topoisomerase IIα (proliferation and DNA repair), caspase-3 (apoptosis) and CD20 (B-lymphocytes) were related to HPV. None of the HR-HPVs but only LR-HPVs were associated with the lesions developed to cancer.