Expression Profile of Circulating Exosomal microRNAs in Leukoplakia, Oral Submucous Fibrosis, and Combined Lesions of Leukoplakia and Oral Submucous Fibrosis

Objectives: This study aims to elucidate the expression of circulating exosomal miRNAs miRNA 21, miRNA 184, and miRNA 145 in the studied groups, including patients with (i) leukoplakia; (ii) oral submucous fibrosis; (iii) oral submucous fibrosis with leukoplakia; (iv) oral squamous cell carcinoma; and (v) healthy individuals.

Study design: An observational study was conducted among 54 patients who reported to the outpatient department of Saveetha Dental College and Hospitals. The patients were divided into three groups: Group I healthy individuals (n = 18), Group II: case group (leukoplakia, OSMF, and leukoplakia and OSMF) (n = 18), and Group III: OSCC (n = 18). Real-time polymerase chain reaction analysis was carried out to assess the expression profiles of miRNA 21, miRNA 184, and miRNA 145. The statistical analysis was calculated using SPSS software version 23.

Results: All three miRNAs showed a statistically significant difference in the one-way ANOVA test between the case group (leukoplakia, OSMF, and leukoplakia and OSMF), healthy group, and OSCC group (p < 0.005). The case group (leukoplakia, OSMF, leukoplakia and OSMF) showed upregulated expression of miRNA 21 and miRNA 184 with threefold change and fourfold change and downregulated expression of miRNA 145 with 1.5-fold change when compared to apparently healthy individuals.

Conclusion: Plasma circulating exosomal miRNAs miRNA 21, miRNA 145, and miRNA 184 expression could be a novel panel of plasma biomarkers to categorise case group (leukoplakia, OSMF, leukoplakia and OSMF) patients with a high risk of malignant transformation.