Authors' Affiliations: 1Structural Genomics Consortium and 2Target Discovery Institute, Nuffield Department of Clinical Medicine, University of Oxford, Oxford; 3School of Cancer Sciences, University of Birmingham; 4Department of Cellular Pathology, Queen Elizabeth Medical Centre, Birmingham; 5Pfizer Worldwide Medicinal Chemistry, Pfizer Worldwide R&D, Ramsgate Road, Sandwich, United Kingdom; 6Laboratory for Childhood Leukemia, Department of Biomedicine, University of Basel and Basel University Children's Hospital, Basel, Switzerland; 7Department of Biochemistry and Molecular Biology, School of Medicine and Health Sciences, George Washington University, Washington, DC; 8Department of Medical Oncology, Dana-Farber Cancer Institute; and 9Department of Medicine, Harvard Medical School, Boston, Massachusetts (At 2013-05-30)