ROS1 and non-small cell lung carcinoma: Therefore, the development of small molecular tyrosine kinase inhibitor (TKI), crizotinib that targets ALK, c-MET/hepatocyte growth factor receptor (HGFR), and ROS1 has been shown to possess superior activity, including longer progression-free survival (PFS) than chemotherapeutic regimens in previously untreated NSCLC patients[32–34].