EGFR and glioblastoma: As an illustration in brain tumors, the EGFR gene is among the most frequently altered oncogene in glioblastoma (GBM), with 57% of tumors showing amplification, mutation, rearrangement, or altered splicing [69], and EGFR has been put forward as a prognostic biomarker in GBM [70], although conflicting results have been reported [71].