Limitations of our study include its retrospective design and inclusion of an unselected heterogeneous cohort of patients with all types of histological (squamous, adenocarcinoma, large cell, undifferentiated) variants of NSCLC, molecular subclassifications (EGFR, ALK, ROS-1, etc) as well as a wide range of anticancer therapies. This evidence concerns the gene ALK and adenocarcinoma.