ALK and non-small cell lung carcinoma: ROS1 was evaluated first in solid tumors in 1987 and it was revealed that in glioblastoma cell line U118MG, ROS1 was altered.224ROS1 rearrangements were observed in NSCLC, initially in 2007, together with the discovery of ALK rearrangements in NSCLC.225–227 Moreover, multiple fusions were detected, most of them in less than 2–3% of these cases.