EGFR and central nervous system cancer: The occurrence of gliomas is frequently associated with molecular changes involving epidermal growth factor receptor (EGFR) and phosphoinositol 3-kinase (PI3K)/Akt/mTOR pathways, as well as mutations of the phosphatase and tensin homolog, p53, DNA repair enzyme O6-methylguanine-DNA methyltransferase, and isocitrate dehydrogenase-1 and -2.