4 Pediatric Hemato-Oncology Department, Hospital Universitario La Paz, Madrid, Spain.
5 Department of Pediatrics, BioCruces Bizkaia Health Research Institute, Hospital Universitario Cruces, University of the Basque Country UPV/EHU, Barakaldo, Spain.
6 Pediatric Oncology and Hematology, Vall d'Hebron Barcelona Hospital Campus, Barcelona, Spain.
7 Pediatric Hemato-Oncology Department, Hospital Universitario Miguel Servet, Zaragoza, Spain.
9 Pediatric Hemato-Oncology Department, Hospital Universitario Son Espases, Mallorca, Spain.
10 Pediatric Oncology and Hematology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain.
11 Pediatric Oncology and Hematology Department, Hospital Clínico Universitario Virgen de la Arrixaca, Instituto Murciano de Investigación Biosanitaria (IMIB), Murcia, Spain.
12 Pediatric Oncology and Hematology Department, Hospital Virgen de la Salud, Toledo, Spain.
13 Pediatric Oncology and Hematology Unit, Hospital Universitario La Fe, La Valencia, Valencia, Spain.
14 Pediatric Oncology and Hematology Department, Hospital Universitario 12 de Octubre, Madrid, Spain.
15 Pediatric Oncology and Hematology Department, Hospital Clinico Universitario de Santiago de Compostela, Santiago de Compostela, Spain.