1. Pediatrics and Adolescent Medicine Aarhus University Hospital Aarhus Denmark
2. Childhood Cancer Research Group Danish Cancer Society Research Center Copenhagen Denmark
3. Pediatric Oncology and Hematology Skåne University Hospital and Department of Clinical Sciences Lund University Lund Sweden
4. Finnish Cancer Registry Helsinki Finland
5. Department of Pediatrics University of Helsinki and Helsinki University Hospital Helsinki Finland
6. The Icelandic Cancer Registry Reykjavik Iceland
7. Faculty of Medicine University of Iceland Reykjavik Iceland
8. Unit of Statistics and Data Analysis Danish Cancer Society Research Center Copenhagen Denmark
9. St. Jude Children's Research Hospital Memphis Tennessee
10. Department of Clinical Medicine Faculty of Health, Aarhus University Aarhus Denmark