IDH1 and neoplasm: CSF is a viable bio fluid to examine contents of EVs.Mutant IDH1 G395A identified in CSF EVs with a sensitivity of 63% and specificity of 100%.CSF EVs generally contained higher levels of mutant mRNA than serum EVs.EVs carry tumour-specific RNA signatures that can be detected non-invasively, supporting the potential of EVs as liquid biopsy tools for glioma diagnosis and monitoring.