Since ROS-1-rearranged NSCLC is rare and detection of ROS1 fusions by a break-apart FISH assay is expensive and labor intensive, diagnostic algorithms and simpler screening methods (e.g., by immunohistochemistry) are needed to identify patients with ROS-1-rearranged NSCLC (104, 106). Here, ROS1 is linked to non-small cell lung carcinoma.