Mir-let-7a Differential Expression in Oral Squamous Cell Carcinoma and Oral Lichen Planus: Insights for Early Diagnostic Biomarker Development.

Background: Early detection of oral squamous cell carcinoma (OSCC) is essential for improving treatment outcomes. Oral lichen planus (OLP) is recognized as a premalignant condition that may progress to OSCC. Recently, microRNAs, particularly miR-let-7a, have emerged as promising biomarkers for gene regulation and early disease diagnosis. This study aimed to evaluate the expression level of miR-let-7a in OSCC and OLP patients, and to compare it with healthy controls, to determine its potential as an early diagnostic marker.

Methods: In this cross-sectional study, serum samples were collected from 36 OSCC patients, 38 OLP patients, and 38 healthy controls. Diagnosis of OSCC and OLP was confirmed via biopsy. Serum RNA was isolated, and after quality verification, cDNA was synthesized. Quantitative real-time PCR (qRT-PCR) was performed to assess miR-let-7a expression across the three groups. Statistical analysis was conducted using SPSS version 16.0.

Results: Significant differences in miR-let-7a expression were observed among the groups. Mean expression levels of miR-let-7a were 1.55 ± 1.19 in OSCC, 2.97 ± 2.00 in OLP, and 7.02 ± 4.10 in the control group (p< 0.001). Lower miR-let-7a expression in OSCC was notably correlated with adverse clinicopathological features, including higher tumor grade (p < 0.001), advanced clinical stage (p= 0.011), larger tumor size (T2) (p< 0.0001), and lymph node involvement (p< 0.0001).

Conclusions: The findings demonstrate that miR-let-7a expression is significantly reduced in OSCC and OLP patients compared to healthy controls, highlighting its potential as an early biomarker for detecting malignant transformation in oral lesions and understanding disease progression in OSCC and OLP.