EGFR and non-small cell lung carcinoma: A total of 67 samples were obtained before EGFR-TKI treatment and after the acquisition of EGFR-TKI resistance, designated as the “pre-treatment” samples (n = 32) and “post-treatment” samples (n = 35), respectively, from patients with EGFR-mutated NSCLC whose tumors had initially responded to EGFR-TKI (Figure 1A).