So both TTF-1 and EGFR can be used to diagnose and therapy for lung adenocarcinomas, because of the restriction of tumor tissues, finance, time, the status of EGFR mutations cannot be detected out timely, for we can detect TTF-1 to guide clinical therapy by immunohistochemical staining which is a simple and economic method that requires less time and manpower, So that for early therapy a reasonable plan can be carried out according to the status of TTF-1 expression. This evidence concerns the gene TTF1 and lung adenocarcinoma.