Association of single nucleotide polymorphisms in MPO and COX genes with oral lichen planus

Oral lichen planus (OLP) is an intractable, chronic inflammatory disorder, and its pathogenesis is still largely unknown. Some literatures supported that genes involved in both oxidative stress and prostaglandin metabolism play an important role in the process of inflammation. To explore their association with OLP, we investigated four single nucleotide polymorphisms (SNPs) from myeloperoxidase (MPO) and cyclooxygenase (COX) genes in 475 Chinese individuals (242 case and 233 controls) by MassArray. Although the genotype distributions had no significant differences between the patients and controls, we found that in different gender, rs2243828 from MPO displayed the statistically significant variance genotype frequencies between patients and controls (P = 0.018 in females, P = 0.035 in males). Moreover, for the major allele recessive model, this SNP also showed a significant difference between case and control groups in males (P = 0.015). In this study, we first observed significant association with MPO polymorphism and OLP risk in different gender groups in Chinese, suggesting MPO polymorphism is a gender-specific risk factor of OLP probably by influencing sex hormone-sensitive elements to regulate inflammatory gene expression networks, and we further revealed that oxidative stress was actually involved in the pathogenesis of this disease. Moreover, these findings inspire us some constructive solutions to the treatment of this disease.