MiR-21 and MiR-155 Expressions in Oral Squamous Cell Carcinoma: A Retrospective Study in Mexican Patients using FFPE Biopsies.

Aim: Oral squamous cell carcinoma (OSCC) is a prevalent malignancy with poor survival outcomes, particularly in regions with high tobacco use and less early detection. MicroRNAs (miRNAs) such as miR-21 and miR-155 have been implicated in tumor progression and viral oncogenesis. This study aimed to evaluate the expressions of miR-21 and miR-155 in OSCC tissues and their association with histological differentiation and HPV infection in a Mexican population. Materials and Methods: This retrospective cross-sectional study included 30 OSCC cases and 30 age- and sex-matched healthy oral tissue controls. Total RNA was extracted from formalin-fixed paraffin-embedded tissue samples, and miR-21 and miR-155 levels were quantified using RT-qPCR. HPV genotyping (types 16 and 18) was performed via endpoint PCR. Statistical analysis included Mann-Whitney Results: MiR-21 and miR-155 were significantly upregulated in OSCC tissues compared to controls ( Conclusion: The overexpression of miR-21 and miR-155 in OSCC supports their potential as diagnostic biomarkers in oral cancer. While their levels were not significantly associated with tumor grade or HPV status, their consistent elevation in malignant tissues warrants further investigation into their mechanistic role in OSCC pathogenesis and their applicability in biomarker panels for early detection, especially in Latin American populations.