ALK and non-small cell lung carcinoma: Crizotinib is an oral small-molecule, multikinase inhibitor of ALK, ROS1, RON, and MET and has been approved for the treatment of advanced NSCLC patients harboring ALK or ROS1 rearrangements; it acts as a type Ia MET tyrosine kinase inhibitor and competes for the ATP-binding site of the RTK, thereby preventing activation of downstream signaling pathways [46].