1 Elizabeth Sokol, MD, Department of Pediatrics and Lurie Children's Hospital, Northwestern University, Chicago, IL; Ami V. Desai, MD, MSCE, and Mark A. Applebaum, MD, Department of Pediatrics and Comer Children's Hospital, University of Chicago, Chicago, IL; Dominique Valteau-Couanet, MD, PhD, Institute Gustave Roussy, Villejuif, France; Julie R. Park, MD, Department of Pediatrics, Seattle Children's Hospital, University of Washington, Seattle, WA; Andrew D.J. Pearson, MD, Paediatric Drug Development, Children and Young People's Unit, Royal Marsden Hospital, London, UK; Gudrun Schleiermacher, MD, PhD, Department of Pediatric, Adolescents, and Young Adults Oncology and INSERM U830, Institut Curie, Paris, France; Meredith S. Irwin, MD, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada; Michael Hogarty, MD, Department of Pediatrics, University of Pennsylvania, Philadelphia, PA; Arlene Naranjo, PhD, Department of Biostatistics, Children's Oncology Group Statistics and Data Center, University of Florida, Gainesville, FL; Samuel Volchenboum, MD, PhD, and Susan L. Cohn, MD, Department of Pediatrics and Comer Children's Hospital, University of Chicago, Chicago, IL; and Wendy B. London, PhD, Dana-Farber/Boston Children's Cancer and Blood Disorders Center, Harvard Medical School, Boston, MA.