University of California San Francisco Medical Center, San Francisco, CA, USA. CIBMTR (Center for International Blood and Marrow Transplant Research), Department of Medicine, Medical College of Wisconsin, Milwaukee, WI, USA. Division of Biostatistics, Institute for Health and Society, Medical College of Wisconsin, Milwaukee, WI, USA. Sarah Cannon BMT Program, Nashville, TN, USA. University of Wisconsin Carbone Cancer Center, Madison, WI, USA. Division of Hematology/Oncology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA. Department of Hematology/Oncology, Hospital Infantil Universitario Nino Jesus, Madrid, Spain. Texas Transplant Institute, San Antonio, TX, USA. Hematology Research Centre, Division of Experimental Medicine, Department of Medicine, Imperial College London, London, UK. University of Cincinnati, Cincinnati, OH, USA. Fred Hutchinson Cancer Research Center, Nashville, TN, USA. Department of Blood and Marrow Transplantation, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA. Mayo Clinic Rochester, Rochester, MN, USA. Seidman Cancer Center, University Hospitals Cleveland Medical Center, Cleveland, OH, USA. Royal Adelaide Hospital, Adelaide, SA, Australia. Hospital Universitario Clementinio Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. Division of Hematology & Oncology, Department of Medicine, Shands HealthCare & University of Florida, Gainesville, FL, USA. Blood and Marrow Transplantation Program, Division of Hematology/Oncology, Department of Internal Medicine, The University of Michigan Medical School, Ann Arbor, MI, USA. Division of Hematology/Oncology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA. Cancer Transplant Institute, Virginia G. Piper Cancer Center, Scottsdale, AZ, USA. Arizona Oncology, Scottsdale, AZ, USA. Ohio State Medical Center, Columbus, OH, USA. Division of Bone Marrow Transplant, Seattle Cancer Care Alliance, Seattle, WA, USA. City of Hope National medical Center, Duarte, CA, USA. Department of Stem Cell Transplantation and Cellular Therapy, The University of Texas M.D. Anderson Cancer Center, Houston, TX, USA.