EGFR and glioblastoma: In the absence of the histologic features of GBM, tumors can also be classified as GBM if one or more of three genetic parameters, namely telomerase reverse transcriptase (TERT) promoter mutation, epidermal growth factor receptor (EGFR) gene amplification, or combined gain of entire chromosome 7 and loss of entire chromosome 10 [+7/−10]) are present [10].