Transcriptomic Profiling Identifies a Distinct Molecular Signature in OSMF-Derived Oral Squamous Cell Carcinoma.

Background: Oral Submucous Fibrosis (OSMF) is a significant global oral health problem, particularly prevalent in India, with a high risk of progression to Oral Squamous Cell Carcinoma (OSCC). This study investigates the molecular mechanisms involved in the transformation of OSMF to OSCC using transcriptomic profiling. Methods: High-throughput RNA sequencing was performed on fresh de novo OSCC samples (n = 8) and OSMF derived OSCC using Illumina-compatible NEXTflex Rapid Directional RNA Sequencing. Normalization and differential gene expression analysis were conducted, and genes exhibiting an absolute log2 fold change of ≥2 with a co-variate-adjusted p-value ≤ 0.05 were identified as significant. Results: Upregulated genes were associated with cytokine and immune responses (ABRA, TTTY14, EIF1AY), cellular proliferation and apoptosis (LINC00314, RPS4Y1, SERPINA5, TRIM63, FABP7), and energy metabolism, indicating metabolic adaptations during malignant progression. Pathway analysis showed increased expression of TNNT1, TNNI1, MYL4, and ACTN3, implicating muscle development and embryonic pathways in OSMF transformation. Conversely, genes related to epithelial differentiation and keratinization (FLG, FLG2, HRNR, TCHH, KRT73), immune regulation and tumor suppression (HLA-G, UNC5D), and metabolic signaling were downregulated, reflecting loss of tissue integrity and immune control. Conclusions: OSMF-derived OSCC exhibits a distinct transcriptomic landscape compared with de novo OSCC, characterized by altered epithelial differentiation, immune modulation, and activation of developmental pathways. The observed gene dysregulation findings establish that OSCC developing in the background of OSMF is molecularly distinct from de novo OSCC, underscoring the biological impact of the pre-existing fibrotic milieu on tumor transcriptional architecture.