Gefitinib, as the first EGFR-TKI approved for the treatment of advanced NSCLC after failure of chemotherapy, has been proved to significantly improve the progression-free survival (PFS) of first-line setting compared with standard chemotherapy in NSCLC patients harboring the EGFR mutation, by series of large-scale phase III clinical trials, i.e. the IPASS [5], WJTOG3405 [6], and NEJ002 trials [7]. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.