No abstract

Oral lichen planus (OLP) is a chronic inflammatory mucocutaneous disease with a potential malignant transformation, characterized by cytotoxic T cells against basal epithelial cells. MicroRNAs (MiRNAs) are short non-coding RNA that plays critical role in gene expression at post-transcriptional levels. Much evidence showed that miRNAs play an important role in regulating immune response and cancer development. The purpose of the present study was to compare the expression of miRNA 27b and miRNA 137 in tissues and saliva between OLP patients and controls by using RT-qPCR and to evaluate their use as biomarkers of disease activity and potential malignant transformation. Our results showed down expression of miRNA 27b and miRNA 137 in tissue and saliva of OLP patients compared to controls; among OLP subgroups, erosive-type miRNA 137 revealed the lowest level in tissue and saliva. In conclusion, alteration of miRNA 27b and miRNA 137 gene expression signify their use as biomarkers for diseases activity and tendency of malignant transformation, and down expression of miRNA 137 especially in erosive-type favors the use of saliva sample as a noninvasive method for monitoring a potential malignant transformation of OLP.

Future studies should investigate the therapeutic potential of miR-137 overexpression in OLP patients.

Background: MicroRNA-27b (miR27b) is a small, non-coding RNA that is involved in physiological keratinocyte differentiation and regulating inflammatory processes. We performed this study to investigate the value of miR27b as a diagnostic marker for oral lichen planus (OLP) and the correlation between CD8 (cytotoxic T-cell marker) and miR27b tissue expression in OLP patients. Methods:Forty participants (including 20 OLP patients and 20 controls) underwent oral biopsy. The obtained specimens were examined by immunostaining and quantitative RT-PCR for CD8 and miR27b tissue expression, respectively. We used the Spearman rank correlation test to evaluate the correlation between both variables.Results: Our analysis showed that in comparison with healthy tissues, OLP tissue samples exhibited significantly higher CD8 levels (P < 0.01), as well as a significant downregulation of miR27b expression (P < 0.0001). Upon comparing different OLP subgroups, no significant difference was detected in terms of miR27b expression; however, the tissue levels of CD8 varied significantly (highest in the erosive subgroup and lowest in the papular/plaque/reticular subgroup). The Spearman rank analysis showed a negative correlation between tissue expression of miR27b and CD8; however, this was not statistically significant (P > 0.05). Further, the receiver operating characteristic curve of tissue miR27b as an OLP biomarker revealed 100% sensitivity and 65% specificity at cutoff value of 4.4. Conclusion:This study demonstrated increased CD8 levels and downregulation of miR27b in OLP tissues, compared to healthy tissues. Moreover, it revealed the potential of miR27b as an OLP disease biomarker. The possible negative correlation between CD8 and miR27b tissue expression requires further investigation in larger studies. K E Y W O R D SCD8, cytotoxic T cells, miR27b, oral lichen planus