RET and lung adenocarcinoma: Currently, approximately 60% of lung adenocarcinomas have now been shown to have mutations (KIF5B-Ret, ROS1, NTRK1, HER2-Neu, to name a few) that may induce and drive these malignancies and the association of TTF-1 status and presence of these driver mutations remains to be elucidated [29-37].