ROS1 and non-small cell lung carcinoma: Numerous reports have implicated the presence of other concomitant mutations in various genes including TP53 in the poor response of ALK-rearranged NSCLC to crizotinib therapy [17, 18]; however, very limited reports have explored the clinical impact of other concomitant mutations on crizotinib therapy of ROS1-rearranged NSCLC.