1. Department of Pediatrics and Adolescent Medicine; The University Hospital Rigshospitalet; Copenhagen Denmark
2. Faculty of Medicine; Institute of Clinical Medicine, University of Copenhagen; Denmark
3. Astrid Lindgrens Barnsjukhus; Stockholm Sweden
4. Department of Pediatric Oncology; The University Hospital Rikshospitalet; Oslo Norway
5. Department of Pediatric Oncology; The National Hospital; Reykjavik Iceland
6. Department of Pediatric Oncology; The University Hospital; Helsinki Finland
7. Department of Pediatric Oncology; Århus University Hospital; Denmark
8. Department of Pharmacology; Mayo Clinic; Rochester Minnesota
9. Section of Biostatistics, Department of Public Health; The University of Copenhagen; Copenhagen Denmark