1. HNJ-CNIO Clinical Research Unit; Hospital Universitario Niño Jesus; Madrid Spain
2. Hôpital des Enfants; CHU; Toulouse France
3. Universite Paris-Saclay, Univ. Paris-Sud, CESP, INSERM; Gustave Roussy; Villejuif France
4. Biostatistics Unit; Gustave Roussy; Villejuif France
5. Department of Pediatric Hemato-Oncology; Istituto Gianina, Gaslini; Genova
6. Department of Pediatric and Adolescent Oncology; Gustave Roussy; Villejuif France
7. Institute of Cancer Research; London UK