Epidermal growth factor receptor (EGFR) is frequently overexpressed in non-small-cell lung cancer (NSCLC) and plays a key role in tumorigenesis.1 Small molecule tyrosine kinase inhibitors (TKIs),such as gefitinib,erlotinib,and icotinib,which can inhibit receptor tyrosine kinase activity of EGFR become clinically available for the treatment of non-small-cell lung cancer (NSCLC).2 NSCLC patients with EGFR mutation have experienced a marked response to EGFR-TKIs therapy.3 Detection of mutations of the EGFR gene is critical for predicting the response to therapy with TKIs.4