1. Department of Paediatric Oncology/Haematology, Otto-Heubner Centre for Paediatric and Adolescent Medicine (OHC), Charité–Universitätsmedizin Berlin, Berlin, Germany
2. Department of Pediatrics, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
3. Department of Clinical Research, Dr. Willmar Schwabe GmbH & Co. KG, Karlsruhe, Germany
4. Institute for Medical Statistics, Unit of Informatics and Epidemiology, University of Cologne, Cologne, Germany