Cerebrospinal Fluid miRNA Profiling as a Potential Liquid Biopsy for Vestibular Schwannomas

Background/Objectives: This study aimed to identify a characteristic miRNA expression profile in the CSF of patients diagnosed with vestibular schwannoma and evaluate its potential for tumor assessment. Methods: In this prospective study, 17 CSF and corresponding tumor samples (seven small tumors-SVS and 10 large tumors-LVS) were collected from patients operated on for VS in a Tertiary Academic Center. The miRNA expression was analyzed using high-throughput RNA sequencing (NovaSeq 6000 Illumina). Data were normalized, and a comparative analysis of miRNA expression rankings was performed between VS patients and a public healthy donor dataset. Functional implications were explored using KEGG pathway enrichment analysis. Results: A total of 1633 miRNAs were identified in all CSF samples derived from VS patients. Comparison with healthy donors revealed a moderate ranking correlation (ρ = 0.39), with significant shifts for specific molecules like hsa-miR-766-3p and hsa-miR-182-5p. Only six miRNAs were found to correlate between CSF and tumor tissue, while 16 exhibited a negative correlation. No statistical correlation was found between tumor size and the CSF miRNA profile. KEGG analysis highlighted enriched pathways, including neurotrophin signaling and focal adhesion. Conclusions: The results of our study support the feasibility of miRNA-based CSF liquid biopsy for VS assessment. However, the results of miRNA expression profiling conducted in tumor tissue cannot be directly transferred into CSF sample analyses. Further studies are warranted to explain this phenomenon and to search for reliable miRNA markers of VS progression in the CSF liquid biopsy specimens.