Three NSCLC cell lines harboring only EGFR-TKI-sensitive EGFR mutation were sensitive to gefitinib (the IC50 values were ranged from 0.0014 to 0.0028 μM), while other NSCLC cell lines harboring wild-type EGFR (n = 9) or TKI-resistant EGFR mutation (n = 2) were resistant (the IC50 were ranged from 5.3 to 32.6 μM). This evidence concerns the gene EGFR and non-small cell lung carcinoma.