1. Department of Pediatrics and Adolescent Medicine Aarhus University Hospital Aarhus N Denmark
2. Department of Pediatrics Institution for Clinical Sciences Queen Silvia Children's Hospital Gothenburg Sweden
3. Department of Pediatrics Queen Mary Hospital and Hong Kong Pediatric Hematology and Oncology Study Group (HKPHOSG) Hong Kong China
4. Department of Pediatrics Landspitali University Hospital Reykjavik Iceland
5. Department of Pediatrics VU University Medical Center Amsterdam The Netherlands
6. Princess Máxima Center for Pediatric Oncology Utrecht The Netherlands
7. Dutch Childhood Oncology Group The Hague The Netherlands
8. Division of Hematology‐Oncology and Stem Cell Transplantation Children's Hospital and Helsinki University Central Hospital Helsinki Finland
9. Department of Pediatrics and Adolescent Medicine Rigshospitalet University of Copenhagen Copenhagen Denmark
10. Department of Pediatrics Ghent University Hospital Ghent Belgium
11. Department of Woman's and Children's Health Uppsala University Uppsala Sweden
12. Division of Pediatric and Adolescent Medicine Oslo University Hospital Oslo Norway
13. Division of Hematology/Oncology The Hospital for Sick Children Toronto Canada