In approximately 50% of GBM specimens, an EGFR amplification can be found, and about 50% of specimens also express the EGFRvIII mutation; these two EGFR modifications greatly amplify EGFR activity which, in turn, impinges on several signaling-dependent pathways regulating key cellular prooncogenic effects such as proliferation, apoptosis, differentiation, and invasiveness. Here, EGFR is linked to glioblastoma.