MGMT and glioblastoma: Studies indicate that PTEN and MGMT mRNA levels in GBM-derived EVs (GDEVs) correlate with tumor grade and therapy response,96 whereas miR-21 in CSF-derived EVs is linked to poor prognosis.73 Moreover, EV-associated epigenetic modifications, including DNA methylation, reflect the molecular profile of tumors,97 supporting their role in real-time GBM monitoring.