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.