Amplification of the MET proto-oncogene accounts for 5–20% of acquired resistance to EGFR TKIs.[9] strong expression of c-Met is associated with poor prognosis of NSCLCs.[10] In this case, we analyzed the potential resistance to EGFR mutations during sequential use of the first- and second-generation TKIs (gefitinib and afatinib) in an advanced lung cancer patient. The gene discussed is MET; the disease is lung cancer.