1. Department of Pediatric Oncology/Hematology; VU University Medical Center; Amsterdam The Netherlands
2. Department of Pediatrics; University Medical Center Utrecht/Wilhelmina Children's Hospital; Utrecht The Netherlands
3. Department of Oncology; Aarhus University Hospital Skejby; Aarhus Denmark
4. Nordic Pediatric Hematology and Oncology group; Gothenburg Sweden
5. Department of Pediatric Oncology; Queen Silvia Children's Hospital; Gothenburg Sweden
6. Department of Pediatric Hematology-Oncology and Stem Cell Transplantation; Ghent University Hospital; Ghent Belgium
7. Belgian Society of Paediatric Haematology Oncology; Utrecht The Netherlands
8. Dutch Childhood Oncology Group; Utrecht The Netherlands
9. Princess Máxima Center for Pediatric Oncology; Utrecht The Netherlands