Detection of Human Papillomavirus 33 in Erosive Oral Lichen Planus

 A correlation is suggested between oral lichen planus (OLP) and the human papillomavirus (HPV) with possible malignant transformation potential in OLP.

 The present study aimed at evaluating the prevalence of HPV-16 and HPV-18 as the most recognized oncogenic subtypes and relatively recently introduced subtype HPV33 in OLP samples.

 This retrospective study was carried out on 32 OLP samples (consisting of 12 reticular and 20 erosive forms) and 20 healthy oral mucosa samples. Polymerase chain reaction (PCR) was undertaken to identify HPV Deoxyribonucleic Acid (DNA). Subsequently, the samples positive for HPV DNA underwent PCR analysis again with the specific primers. The data were analyzed statistically by Fisher’s exact test regarding the significance level of lower than 0.05.

 Eight out of 32 OLP samples (25%) and none of the 20 normal mucosa samples (0%) exhibited HPV DNA. The presence of HPV in the OLP group was significantly higher than that in the normal mucosa (P = 0.014). Also, all the samples that exhibited HPV DNA were registered as the erosive form. Besides, one sample (3.12%) exhibited the 873-bp band, which was attributed to HPV-18, and 7 samples (21.87%) exhibited the 300-bp band, which was attributed to HPV-33.

 Based on the recent findings in the current study of the Iranian population, the presence of high-risk HPV subtypes, whether primarily or as a secondary infection, can suggest the malignant transformation potential for the studied OLP samples. The exclusive presence of these subtypes in the erosive type of this lesion and the noticeable presence of HPV-33 might reflect this issue’s importance. However, further studies are necessary to evaluate the possibility of a higher proliferation rate of HPV in erosive lichen planus and identify its possible malignant transformation mechanism.