Since its first discovery in lung adenocarcinoma in 2004, somatic EGFR mutation - one of the most important and targetable driver mutations found in non-small cell lung cancer (NSCLC) - has been extensively validated as an effective indicator of sensitivity to EGFR tyrosine kinase inhibitors (TKIs), as well as a prognosticator for patients [18]. This evidence concerns the gene EGFR and lung adenocarcinoma.