ROS1 and lung carcinoma: MET can be distinguished from numerous other proto-oncogenes by permitting 3 distinct types of genomic alterations to induce oncogenesis that are clinically significant: fusion, mutation, and amplification.5 In contrast to MET mutations and amplification, MET fusions are less common, but have been identified in multiple tumor types including lung cancer and glioblastoma.11,12 Crizotinib is a small-molecule tyrosine kinase inhibitor that inhibits MET, anaplastic lymphoma kinase (ALK), and C-ros oncogene 1, receptor tyrosine kinase (ROS1).