1. Pediatric Oncology Unit; Centre Oscar Lambret; Lille France
2. Epidemiology and Biostatistics Unit; Institut Gustave Roussy; Villejuif France
3. Pediatric Oncology Department; Institut Gustave Roussy; Villejuif France
4. Pediatric Hemato Oncology Department; CHU Nantes; France
5. Pediatric Hemato Oncology Department; Hôpital Trousseau; Paris France
6. Pediatric Hematology; CHU; Lille France
7. Institut d'Hémato Oncologie Pédiatrique; Lyon France
8. Pediatric Hematology Department; Hôpital Robert Debré; Paris France
9. Pediatric Oncology Department; Hôpital de la Timone; Marseille France
10. Pediatric Hemato Oncology Unit; American Memorial Hospital; Reims France
11. Pathology Department; Institut Gustave Roussy; Villejuif France