Crizotinib (Xalkori, Pfizer, Inc.)was initially approved for the treatment of patients with metastatic ROS1-positive nonsmall cell lung cancer tumors, and has subsequently been approved for pediatric patients, 1 year of age and older with unresectable, recurrent, or refractory inflammatory ALK-positive myofibroblastic tumors [46]. The gene discussed is ROS1; the disease is lung cancer.