P16 AND MGMT GENE METHYLATION IN CHRONIC MECHANICAL IRRITATION OF THE ORAL MUCOSA

Objective Chronic mechanical irritation (CMI) has been proposed as a risk factor for oral cancer. Epigenetic alterations, particularly methylation, have been mentioned as early events in carcinogenesis, and it has been proposed that CMI could induce them. Thus, the aim of this study is to describe p16 and MGMT gene methylation in a specific CMI lesion: chronic traumatic ulcer (CTU). Study Design A split-mouth design was used, and 2 samples per individual were taken using cytobrush: the CTU lesion and clinically normal mucosa of a contralateral site. After extracting DNA, p16 protein and MGMT gene methylation status were assessed using quantitative polymerase chain reaction (PCR). The statistical analysis was performed by McNemar test. Results Twenty-seven patients were studied with a mean age of 59.1 years. CTU evolution time showed an average of 18.4 months. On CTU, methylation of both p16 and MGMT presented a significant difference (P Conclusions CMI-affected sites showed consistently more methylation of p16 and MGMT than mucosa devoid of CMI. Since in each case both control and study samples were from the same individual, effects of confounders were reduced. This study suggests that CMI could foster carcinogenesis through epigenetic alterations.