EGFR and glioblastoma: The molecular biomarkers of GBM are MGMT promoter methylation, IDH mutation, chromosome 1p/19q deletion, TERT promoter mutation, TP53 mutation, PTEN (Phosphatase and tensin homolog) mutation, CDKN2A (cyclin-dependent kinase inhibitor 2A) deletion, EGFR amplification, PDGFRA (platelet-derived growth factor receptor A) amplification, NF1 (Neurofibromin 1) mutation, MDM2 (Mouse double minute 2 homolog) amplification, and many others [40,41].