EGFR and lung adenocarcinoma: Human lung adenocarcinoma H1975 cells, harboring an EGFR‐L858R‐sensitive mutation or an EGFR‐T790M‐resistant mutation, were resistant to the first‐generation EGFR‐TKI gefitinib, but were sensitive to the third‐generation EGFR‐TKI osimertinib (Fig. 1A).