EGFR and glioblastoma: Several genetic alterations of cancer cause induction of cellular proliferation through the epidermal growth factor receptor (EGFR)-Ras-Raf-mitogen activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK; MEK)-ERK-MAPK pathway, including EGFR amplifications (colorectal, pancreatic and lung cancers) and mutations (lung adenocarcinomas and glioblastoma), and activating mutations of Ras (pancreatic, papillary thyroid, colon and lung cancers) and Raf (melanoma, papillary thyroid and colon cancers) [11].