To gain insights into the crucial events of lung cancer development, we adopted as prototype of aberrant EGFR activation a key genetically engineered murine model (GEMM) of NSCLC, carrying two recurrent activating mutations identified in patients (15), that is, the L858R-T790M transgenic mice (EGFRTL mice; 16). The gene discussed is EGFR; the disease is non-small cell lung carcinoma.