Human papillomavirus in oral atrophic lichen planus lesions

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.

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.

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.

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.