From Tissue Signaling to Liquid Biopsy: A pAKT-Driven microRNA Model for Oral Squamous Cell Carcinoma Detection

Background Oral squamous cell carcinoma (OSCC) develops through a multistep progression from oral potentially malignant disorders (OPMDs), yet reliable biomarkers that reflect the molecular mechanisms driving malignant transformation are lacking. Aberrant activation of the PI3K/AKT pathway is a key event in epithelial carcinogenesis, but its integration with upstream regulatory microRNAs (miRNAs) in oral cancer progression remains poorly understood. Methodology Phosphorylated AKT (pAKT) expression was evaluated by immunohistochemistry in oral epithelial tissues spanning the OPMD-OSCC continuum. In parallel, circulating serum levels of the oncogenic microRNA miR-196a1 and the tumor-suppressive microRNA miR-126 were quantified using quantitative real-time PCR. Associations between tissue pAKT expression, circulating miRNA levels, and clinicopathological parameters were assessed. Diagnostic performance of individual and combined circulating miRNA markers for distinguishing OSCC from OPMDs was evaluated using receiver operating characteristic analysis and multivariable logistic regression Results Tissue analysis revealed a progressive increase in pAKT expression with advancing histological severity, indicating a stepwise activation of the PI3K/AKT signaling pathway during malignant transformation. Serum profiling revealed significant upregulation of miR-196a1 and concomitant downregulation of miR-126 across disease progression, with strong associations to histological grade and tobacco exposure. Loss of miR-126, a negative regulator of PI3K signaling, showed marked biological concordance with increased tissue pAKT expression. Integration of tissue pAKT status with reciprocal microRNA dysregulation enabled robust discrimination between premalignant and malignant lesions with strong internal validation. Conclusion This study identifies a novel pAKT-microRNA regulatory axis in oral carcinogenesis, wherein oncogenic gain of miR-196a1 and loss of miR-126 converge on PI3K/AKT pathway activation. Integration of tissue pAKT alterations with circulating microRNA profiles provides mechanistic context for the observed molecular differences across OPMDs and OSCC. The combined circulating miRNA model demonstrated strong discriminatory performance for distinguishing OSCC from OPMDs, supporting further validation of this tissue-circulating biomarker framework in independent cohorts.