Research progress on microRNAs connected with oral lichen planus

Oral lichen planus (OLP) is a common chronic inflammatory disease with unclear etiology, in which disorder of the cell-mediated local immune response plays an important role. MicroRNAs (miRNAs) have been found to play an important role in the occurrence and development of inflammatory responses and autoimmune diseases. In recent years, many studies have reported that miRNAs may be related to OLP. According to a literature review, high expression of miRNA-19a and low expression of miRNA-122, miRNA-199, miRNA-138, miRNA-635 and miRNA-578 may be related to the occurrence of OLP by regulating cytokines such as interleukin, interferon and tumor necrosis factor. The low expression of miRNA-125a and the high expression of miRNA-132, miRNA-146a and miRNA-155 may be related to the severity of OLP by influencing the differentiation of CD4⁺ T cells in the Th1/Th2 subgroup. High expression of miRNA-26a, miRNA-29a and miRNA-31 and low expression of miRNA-27b, miRNA-200a and miRNA-137 may be associated with malignant risk of OLP through functionally related genomes, transcription factors and miRNA coregulatory networks. Some deficiencies remain in current studies. For example, many studies using microarrays to screen differentially expressed miRNAs have not been further grouped according to the type of OLP or cancer risk.