BIOM-76. EXPLORING CSF MICRORNA SIGNATURES AS DIAGNOSTIC BIOMARKERS IN IDH-WILDTYPE DIFFUSE GLIOMAS

Abstract The most prevalent malignant tumors of the central nervous system are adult-type diffuse gliomas. Isocitrate dehydrogenase (IDH) mutations are identified in a subset of diffuse gliomas, leading to two distinct subtypes of gliomas: IDH-wildtype and IDH-mutant. In comparison to IDH-mutant gliomas, IDH-wildtype gliomas tend to be associated with a more rapid progression and lower overall survival rates. The analysis of differentially expressed microRNAs (DE-miRNAs) in cerebrospinal fluid (CSF) of IDH-wildtype diffuse gliomas could provide an effective and non-invasive approach to assist in the early diagnosis, classification, and management of the disease. Extracellular vesicle (EV)-derived miRNAs obtained from the CSF of 11 patients with IDH-wildtype diffuse gliomas and 8 controls were analyzed by microRNA sequencing (miRNA-seq). DE-miRNAs were defined using p-value≤0.05 and absolute log2 fold change (log2FC) ≥1. Candidate DE-miRNAs were validated by qRT-PCR in 24 samples (15 IDH-wildtype vs. 9 control) using the 2-ΔΔCT method, followed by receiver operating characteristic (ROC) curve analysis. Hsa-miR-24-3p was used as the internal control. miRNA-seq analysis identified hsa-miR-484, hsa-miR-223-3p, hsa-miR-1246, hsa-miR-323a-3p, hsa-miR-106b-3p, hsa-miR-21-5p, hsa-miR-15a-5p, has-miR-15b-5p, and hsa-miR-92a-3p among the top 20 upregulated miRNAs in the CSF of patients with IDH-wildtype diffuse gliomas. Further analysis by qPCR showed that patients with IDH-wildtype diffuse gliomas had significantly higher levels of has-miR-21-5p (2.28 ± 2.33) compared to control subjects (-2.22e-007 ± 1.08, p=0.012). The ROC curve analysis revealed an area under the curve (AUC) of 0.84 (95% CI, 0.68-1.0) for has-miR-21-5p CSF levels in distinguishing IDH-wildtype diffuse gliomas from control subjects. EV-derived miRNAs in CSF, including has-miR-21-5p, have the potential to distinguish IDH-wildtype diffuse gliomas from control individuals in a minimally-invasive manner and serve as diagnostic biomarkers.