However, it appears that EGFR-associated alterations in glioblastoma lack prognostic significance, which is multifactorial because of the difference in structural mutation location (extracellular in glioblastoma versus intracellular in lung cancer) as well as the presence of regulatory downstream circuits that can lead to cell growth independent of EGFR status [158,159]. This evidence concerns the gene EGFR and glioblastoma.