EGFR mutations in GBM cluster in the extracellular (EC) domain and include in-frame deletions (such as the common “variant III” del 6-273) and missense mutations (A289V, A289D, T263P, G598V). In vitro and in vivo studies reveal anchorage-independent growth and tumorigenic potential when the A289 and G598 variants are stably expressed in NIH-3T3 cells. The A289 and G598 mutations sensitize Ba/F3 cells to erlotinib in vitro according to some reports, although other reports state glioma-specific EGFR EC mutants are poorly inhibited by EGFR inhibitors that target the active kinase conformation (e.g., erlotinib). The A289 variant has been reported to show sensitivity towards BAY846, a tyrosine kinase inhibitor in brain tumors. In addition, according to some reports, inhibitors which bind to the inactive EGFR conformation potently inhibit EGFR EC mutants and induce cell death in EGFR mutant GBM cells.