Exosomal MicroRNAs as Emerging Liquid Biopsy Biomarkers in Glioma: Diagnostic, Prognostic, and Therapeutic Implications for Neuro-Oncology.

Glioblastoma remains the most aggressive malignant brain tumor, with limited survival despite advances in surgery, radiotherapy, and chemotherapy. Current diagnostic modalities are insufficient for early detection and precise monitoring of disease progression, prompting interest in liquid biopsy-based biomarkers. Exosomal microRNAs (miRNAs) have been highlighted as significant biomarkers due to their stability and involvement in tumor progression. This narrative review evaluates current evidence regarding the diagnostic, prognostic, and therapeutic significance of exosomal and extracellular vesicle-associated miRNAs in brain tumors, particularly gliomas. Data were collected from PubMed and Google Scholar, and eight original articles published between 2016 and 2026 were included after careful screening. The findings demonstrated dysregulated expression of exosomal miRNAs, including miR-29b, miR-210, miR-301a, miR-454-3p, and miR-2276-5p, which were significantly associated with tumor grade, recurrence, survival, and treatment response. The majority of studies reported strong diagnostic performance, with receiver operating characteristic/area under the curve values ranging from 0.80 to 0.93, while mechanistic analyses implicated these miRNAs in oncogenic pathways, including PTEN/AKT signaling, hypoxia-mediated progression, autophagy regulation, and angiogenesis. Overall, exosomal miRNAs demonstrate considerable potential as noninvasive biomarkers for prognostication and therapeutic targeting, while their dynamic preoperative alterations further suggest utility in disease monitoring.