Abstract: To the Editor:Epidermal growth factor receptor (EGF R) is overexpressed in non-small cell lung cancer (NSCLC) and contains a tyrosine kinase inhibitor (TKI) domain which acts as an important therapeutic target.Previous studies have observed the efficacy of EGFR-TKIs in the most commonly targeted exon mutations (19 and 21).This study was to investigat the pathologic features of uncommon EGFR mutations and the clinical efficacies of EGFR-TKIs treatment.