1. Childhood Cancer Research Unit, Department of Women’s and Children’s Health, Karolinska Institute, Stockholm, Sweden;
2. Theme of Children’s and Women’s Health, Karolinska University Hospital, Stockholm, Sweden;
3. Direzione Generale, Azienda Sanitaria Provinciale, Ragusa, Italy;
4. Servicio de Pediatria, BioCruces Health Research Institute, Hospital Universitario Cruces, University of the Basque Country, Universidad del Pais Vasco–Euskal Herriko Unibertsitatea (UPV/EHU), Barakaldo, Spain;
5. Division of Hematology/Oncology, The Hospital for Sick Children, Toronto, ON, Canada;
6. Division of Bone Marrow Transplant and Immune Deficiency, Cincinnati Children's Hospital Medical Center, Cincinnati, OH;
7. Department of Pediatrics, Graduate School of Medicine, Ehime University, Ehime, Japan;
8. Pediatric Hematology and Oncology, University Medical Center Hamburg, Hamburg, Germany;
9. Center for Cancer and Immunology Research, Children's Research Institute, Children's National Medical Center, Washington, DC;
10. Texas Children's Cancer Center, Baylor College of Medicine, Houston, TX;
11. University Clinic of Pediatrics, St. Anna Children's Hospital, Medical University of Vienna, Vienna, Austria;
12. Clinical Epidemiology Unit, Department of Medicine, Solna, Karolinska Institutet, Stockholm, Sweden;
13. Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro, Sweden;
14. Department of Epidemiology and Public Health, University College London, London, United Kingdom;
15. Department of Pediatrics, Watford General Hospital, Watford, United Kingdom;
16. Department of Pediatric Hematology and Oncology, Hospital de Niños Dr Pedro De Elizalde, Buenos Aires, Argentina;
17. Department of Pediatrics, Hospital de Clinicas Jose de San Martin, Buenos Aires, Argentina;
18. Instituto de Farmacología, Universidad de Buenos Aires, Buenos Aires, Argentina; and
19. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina