1. Institut d’Investigacions Biomèdiques August Pi i Sunyer, Barcelona, Spain;
2. Centro de Investigación Biomédica en Red de Cáncer, Madrid, Spain;
3. Hematopathology Unit, Hospital Clínic de Barcelona, University of Barcelona, Barcelona, Spain;
4. Pediatric Oncology Department, Hospital Sant Joan de Déu, Esplugues de Llobregat, Spain;
5. Pediatric Oncology Department, Hospital Universitario y Politécnico La Fe de Valencia, Valencia, Spain;
6. Department of Genetics, Physical Anthropology, and Animal Physiology, Faculty of Science and Technology, University of the Basque Country, Universidad del Pais Vasco/Euskal Herriko Unibertsitatea, Leioa, Spain;
7. Pediatric Oncology Unit, Hospital Universitario Cruces Osakidetza, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain;
8. Pathology Department, Hospital Universitari Vall d’Hebron, Barcelona, Spain;
9. Pathology Department, Hospital Universitario Cruces Osakidetza, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain;
10. Pathology Department, Hospital Sant Joan de Déu, Esplugues de Llobregat, Spain;
11. Pathology Department, Hospital Universitario 12 de Octubre, Madrid, Spain;
12. Pathology Department, Complejo Hospitalario de Navarra, Pamplona, Spain;
13. Pediatric Oncology Department and
14. Pathology Department, Hospital Universitario Infantil Niño Jesus, Madrid, Spain;
15. Pediatric Oncology Department, Complejo Hospitalario de Navarra, Pamplona, Spain;
16. Pediatric Oncology Department, Hospital Universitari Vall d’Hebron, Barcelona, Spain;
17. Pediatric Oncology Department, Hospital Clínico Universitario de Valencia, Valencia, Spain;
18. Pediatric Oncology Department, Hospital Universitario 12 de Octubre, Madrid, Spain;
19. Pathology Department, Hospital Trias i Pujol, Badalona, Spain;
20. Pathology Department and
21. Pediatric Oncology Department, Hospital de Sant Pau i la Santa Creu, Barcelona, Spain;
22. Pediatric Oncology Department, Hospital Virgen del Rocio, Sevilla, Spain;
23. Laboratory of Pathology, National Institutes of Health, Bethesda, MD;
24. Department of Pathology and Laboratory Medicine, Children’s Hospital Los Angeles, Los Angeles, CA;
25. Department of Research, Mayo Clinic, Scottsdale, AZ;
26. Department of Laboratory Medicine and Pathology, Mayo Clinic, Phoenix, AZ; and
27. Institute of Pathology, University Hospital Tübingen, Eberhard Karls University of Tübingen, Tübingen, Germany