Icotinib is a quinazoline derivative that reversibly binds to the ATP binding site of EGFR protein, thereby preventing lung cancer cells from completing the signal transduction cascade and stopping the cell from overproliferating.13 It was developed and confirmed efficacy as the first‐generation TKIs in a registered clinical trial in China.14 Here, we have presented the clinical response and genetic profiling of resistance to icotinib in advanced NSCLC patients with EGFRum from a retrospective study in China. The gene discussed is EGFR; the disease is lung cancer.