1. Pediatric Surgical Center of Amsterdam; Emma Children's Hospital AMC and VU University Medical Centre; Amsterdam The Netherlands
2. Netherlands Cancer Institute - AVL; Amsterdam The Netherlands
3. Leeds Teaching Hospitals Trust; Leeds UK
4. St. George's Healthcare NHS Trust; London UK
5. University-Hospital of Padua; Padua Italy
6. Hôpital Trousseau; Paris France
7. Children's Hospital; University of Tübingen; Tübingen Germany
8. Dr. von Hauner Children's Hospital; Ludwig-Maximilians-University; Munich Germany
9. University of Homburg/Saar; Germany
10. Institut d'Hémato-Oncologie Pédiatrique; Lyon France
11. Institute of Child Health; University College London & Great Ormond Street Hospital; London UK
12. Erasmus MC Sophia Children's Hospital; Rotterdam The Netherlands
13. Academic Medical Center; Amsterdam The Netherlands
14. Childhood Cancer Research Unit; Karolinska Institutet; Astrid Lindgren Children's Hospital; Stockholm Sweden
15. AMC; Paediatric Oncology; The Netherlands
16. Department of Pediatric Surgery; Marciniak Hospital; Wroclaw and Medical University; Chair of Emergency Medicine; Wroclaw Poland