Treatment with tyrosine kinase inhibitors (TKIs) is strongly recommended for patients with advanced non–small cell lung cancer (NSCLC) harbouring epidermal growth factor receptor (EGFR) mutations that are sensitive to TKIs, such as exon 19 deletion (19-Del) and exon 21 L858R (21-L858R) [1, 2]. Here, EGFR is linked to lung cancer.