EGFR and glioblastoma: GBM and stromal cells release tumor-associated EVs into bodily fluids such as plasma, serum, CSF, and urine, providing an accessible liquid biopsy tool for disease monitoring and molecular profiling.89 Elevated EV concentrations in the peripheral blood of GBM patients, independent of specific molecular alterations (EGFR amplification, PTEN deletion, MGMT expression, and IDH mutations),90 suggest their broad applicability in GBM detection, prognosis, and relapse prediction.