EGFR and central nervous system cancer: We further found that the expression of EGFR in serum EVs could distinguish high-grade glioma patients from low-grade ones, and the level of EGFR in serum EVs correlated well with Ki-67-LI in tumor tissue, a widely accepted marker for the proliferation of glioma, indicating EGFR+ EVs as an indicator for the malignancy of glioma.