1. Department of Pediatrics Goethe‐University Frankfurt Frankfurt Germany
2. Pediatric Hematology and Oncology, Pediatrics III University Hospital Essen Essen Germany
3. Department of Pediatrics Aarhus University Hospital Skejby Aarhus Denmark
4. Princess Máxima Center for Pediatric Oncology Utrecht The Netherlands
5. Division of Leukemia and Lymphoma, Children's Cancer Center National Center for Child Health and Development Tokyo Japan
6. Division of Hematology/Oncology, The Hospital for Sick Children University of Toronto Toronto Ontario Canada