Altered microRNA expression profile with miR-27b down-regulation correlated with disease activity of oral lichen planus

Oral Diseases (2012) 18 , 265–270 Background: Increasing evidence indicates that microRNAs (miRNAs) play a vital role in the pathogenesis of inflammatory and autoimmune diseases. The objective of this study was to investigate the altered miRNA expression profile in patients with oral lichen planus (OLP) and determine the miR‐27b expression. Methods: We compared miRNA expression patterns in oral biopsy specimens from patients with OLP (n = 3) with those from normal controls (n = 3) using microarray technology. We further assessed the miR‐27b expression in specimens from patients with OLP (n = 53) against controls (n = 34) using real‐time quantitative PCR (RT‐QPCR), and miR‐27b expression in specimens from patients with OLP (n = 15) against controls (n = 12) using in situ hybridization (ISH). Results: Using microarray analysis, a total of 46 differentially expressed miRNAs with more than 2‐fold change were identified, including 8 up‐regulated and 38 down‐regulated miRNAs. Both RT‐QPCR and ISH analyses revealed that miR‐27b was significantly down‐regulated in OLP tissue, and miR‐27b expression was even more suppressed in atrophic‐erosive OLP than in reticular OLP. In addition, miR‐27b was found to be expressed in the epithelial keratinocyte layer of both normal and OLP tissues. Conclusion: These data indicate that miRNAs may be the novel candidate biomarkers for the implication of miRNAs in the pathogenesis of OLP.