Exosome-Derived microRNAs as Liquid-Biopsy Biomarkers in Laryngeal Squamous Cell Carcinoma: A Narrative Review and Evidence Map

Exosome-derived microRNAs (miRNAs) have been proposed as minimally invasive biomarkers for laryngeal squamous- cell carcinoma (LSCC). Because oral and maxillofacial surgeons are integral to head-and-neck oncologic and reconstructive pathways, such liquid-biopsy signals could support perioperative decision-making (selection for organ-preserving surgery), margin surveillance, and reconstructive planning. We conducted a preregistered, protocol-driven search of PubMed/MEDLINE, Web of Science, and Scopus from inception to 1 June 2025. Given the very small number of clinically comparable diagnostic studies, discordant index tests/thresholds, and high heterogeneity, we did not perform quantitative pooling or publication-bias testing. Instead, we undertook a narrative synthesis and constructed an evidence map; risk of bias tools (QUADAS-2; ROBINS-I) were applied descriptively to inform qualitative confidence. Nine studies were formally analysed based on eligibility to the study topic. Two serum-based case-control investigations (111 LSCC, 80 controls) reported areas under the ROC curve of 0.876 (miR-21 + HOTAIR) and 0.797 (miR-941), with corresponding sensitivities of 94% and 82%. Seven mechanistic papers showed that vesicular cargos-including miR-1246, circPVT1, and LINC02191-drive STAT3-dependent M2 polarisation, NOTCH1-mediated stemness, Rap1b-VEGFR2 angiogenesis, and glycolytic re-programming, producing 1.6-2.6-fold increases in invasion, tube formation, or xenograft growth. Only three studies fulfilled MISEV-2018 characterisation criteria, and none incorporated external validation. This narrative review and evidence map identifies promising but preliminary diagnostic signals and biologically plausible mechanisms for exosomal miRNAs in LSCC; however, the evidence is sparse, single-region, methodologically inconsistent, and at high risk of bias. Findings do not support clinical implementation at this stage. Priorities include harmonised EV workflows, prespecified thresholds, and prospective, multi-centre validation.