EGFR and glioblastoma: We selected three short-term GBM cell cultures from our laboratory with differences for EGFR amplification: HC-444 culture without EGFR amplification (N-amp), HC-534 with a low EGFR amplification level (L-amp) and HC-466 with high EGFR amplification level (H-amp) (Supplementary Material Table S1).