EGFR and glioblastoma: Therefore, we first identified GBM lines with predominantly EGFR amplification (EGFR+, representing CL GBMs), both PDGFRA and EGFR amplifications (in agreement with the heterogeneous nature of GBMs that are observed), as well as lines that bear predominantly PDGFRA amplification (PDGFRA+, representing PN GBMs) (Figure S1A).