EGFR and glioblastoma: Epidermal growth factor receptor variant III (EGFRvIII), characterized by deletion of exons 2 through 7 with insertion of a glycine residue at the junction between exon 1 and 8 of EGFR, is a consistent tumor specific mutation that is widely expressed in GBM, with an overall prevalence of 20–30% in GBM patients (19, 20).