EGFR tyrosine kinase inhibitors (TKIs), such as the 1st-generation erlotinib and gefitinib, the 2nd-generation afatinib, and the 3rd-generation osimertinib have revolutionized the treatment of non-small cell lung cancer (NSCLC)1–4. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.