Differential expression of hsa-miR-21-5p and hsa-miR-26a-5p in oral squamous cell carcinoma: A Single Centre pilot study.

PURPOSE: Oral squamous cell carcinoma (OSCC) is a leading cause of cancer mortality, and reliable molecular markers are needed, particularly in resource-limited settings. This pilot study evaluated the expression of two microRNAs, hsa-miR-21-5p and hsa-miR-26a-5p, in OSCC tissue compared with normal oral tissue, as a hypothesis-generating step toward biomarker development. METHODS: In this single-centre case-control pilot study, 16 histopathologically confirmed OSCC tissues and 16 histologically normal control tissues were analysed. Total RNA was extracted and reverse-transcribed, and hsa-miR-21-5p and hsa-miR-26a-5p were quantified by qRT-PCR using U6 snRNA as reference gene and the 2^-ΔΔCt method. Group differences were assessed using the Mann-Whitney U test with Hodges-Lehmann median differences, and receiver operating characteristic (ROC) analysis with bootstrap and leave-one-out internal validation. RESULTS: hsa-miR-26a-5p was consistently upregulated in OSCC (Hodges-Lehmann ΔCt difference 3.59, 95% CI 3.02-4.19; p < 0.001) and completely separated OSCC from controls (AUC 1.000). hsa-miR-21-5p showed a smaller, inconsistent difference (1.21, 95% CI 0.26-1.99; p = 0.012; AUC 0.758). Neither marker was associated with tumour stage, grade, age, or sex. As the cohort comprised only advanced (Stage III-IV) disease within a single sample set, this separation is reported descriptively rather than as validated diagnostic accuracy. CONCLUSION: hsa-miR-26a-5p is robustly overexpressed in advanced OSCC and warrants validation in larger, independent, stage-diverse cohorts before any diagnostic application, which would require validation is considered.