1. Emma Children’s Hospital, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Pediatric Oncology, Cancer Center Amsterdam, 1007 MB Amsterdam, The Netherlands
2. Princess Máxima Center for Pediatric Oncology, 3584 CS Utrecht, The Netherlands
3. Cancer Center Amsterdam, Amsterdam University Medical Center, Vrije Universiteit Medical Center, 1007 MB Amsterdam, The Netherlands
4. Department of Haematology/Oncology, Royal Hospital for Sick Children, Edinburgh EH16 4TJ, UK
5. Department of Haematology/Oncology, Erasmus MC-Sophia Children’s Hospital, 3000 CA Rotterdam, The Netherlands
6. Department of Pediatric Hematology and Oncology, Universitätsklinikum Giessen und Marburg GmbH, Standort Giessen—Zentrum für Kinderheilkunde und Jugendmedizin, Feulgenstr. 12, 35392 Giessen, Germany
7. Clinic for Paediatric and Adolescent Medicine, Medical Faculty of the Martin-Luther University of Halle, Ernst-Grube-Str. 40, 06120 Halle, Germany
8. Department of Pediatric Hematology and Oncology, Faculty Hospital Motol and 2nd Medical Faculty, Charles University, V Úvalu 84, 150 06 Prague 5, Czech Republic
9. Department of Paediatric Haematology and Oncology, KU Leuven, UZ Leuven, Herestraat 49, 3000 Leuven, Belgium
10. Pediatric Hematology and Oncology, St. Anna Children’s Hospital, Medical University of Vienna, Kinderspitalgasse 6, A-1090 Wien, Austria
11. Department of Reproductive Medicine & Gynecology, University Medical Center Utrecht, 3584 CX Utrecht, The Netherlands