ALK and non-small cell lung carcinoma: Although the reported frequency of these alterations in an unselected NSCLC population is estimated to be <3% [32,33,34], they rarely overlap with EGFR mutations and ALK fusions [35] and are prevalent in young, never-smoker patients [36,37], defining ROS1-positive NSCLC as a unique subset of patients with a potentially targetable driver oncogene.