Evaluating the role of tissue microRNA-27b as a diagnostic marker for oral lichen planus and possible correlation with CD8.

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.

Evaluating the accuracy of microRNA27b and microRNA137 as biomarkers of activity and potential malignant transformation in oral lichen planus patients.

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.

Correlation between tissue expression of microRNA-137 and CD8 in oral lichen planus.

OBJECTIVES: Oral lichen planus (OLP) is a chronic, inflammatory condition, classified by the World Health Organization as a premalignant lesion. We performed this study to evaluate the correlation between microRNA-137 (miR-137) and CD8 oral tissue expression in OLP patients. MATERIALS AND METHODS: Twenty OLP patients [classified into three groups: (a) papular, reticular, or plaque; (b) atrophic; and (c) erosive] and 20 healthy controls were subjected to biopsy of the oral mucosa. To evaluate CD8 tissue expression, we performed immunohistochemical examination, followed by immunostaining and computerized quantification. The expression of miR-137 was evaluated using real-time quantitative PCR. We used SPSS software (version 15 for windows) to perform the statistical analysis. RESULTS: Our analysis showed an increased tissue expression of CD8 (p < 0.01) and reduced expression of miR-137 (p < 0.001) in OLP patients, compared to the control group. Moreover, there was a statistically significant difference (p = 0.001) between OLP subgroups in terms of CD8 tissue expression [highest in erosive OLP and lowest in papular/reticular/plaque OLP]. However, these subgroups showed no significant difference (p = 0.168) in terms of miR-137 expression. A negative correlation (p < 0.05) between tissue expression of miR-137 and CD8 was noted with a varying correlation coefficient in different OLP subgroups (-0.250 in erosive OLP, -0.491 in atrophic OLP and -0.616 in papular/reticular/plaque OLP). CONCLUSIONS: Our findings indicate reduced expression of miR-137 and a reverse correlation between tissue expression of miR-137 and CD8 in the oral mucosa of OLP patients. CLINICAL RELEVANCE: Future studies should investigate the therapeutic potential of miR-137 overexpression in OLP patients.