Epidermal growth factor receptor (EGFR) T854A mutation in exon 21 is an uncommon EGFR mutation in patients with non-small cell lung cancer (NSCLC).[1] It was reported that EGFR T854A is a secondary EGFR mutation after first- and second-generation EGFR tyrosine kinase inhibitors (TKIs).[2,3] The resistance mechanism of EGFR T854A is similar to T790M, substitution produces an enhanced affinity for ATP, thus further reducing the ability of ATP-competitive reversible EGFR TKIs to bind to the tyrosine kinase domain of EGFR. This evidence concerns the gene EGFR and non-small cell lung carcinoma.