EGFR and glioblastoma: Aberrant signaling of the epidermal growth factor receptor (EGFR) plays a crucial role in the pathogenesis of primary brain cancers such as glioblastoma and metastatic lung cancer.2,3 The EGFR pathway is activated with EGFR amplification and EGFRvIII mutations in over 60% of patients with glioblastoma.4 In addition, there is much heterogeneity with multiple other signaling pathways that may limit response with single agents.