1. German Childhood Cancer Registry, Institute for Medical Biostatistics, Epidemiology and Informatics (IMBEI), University Medical Centre of the Johannes Gutenberg University Mainz, Mainz, Germany;
2. Children’s Hospital, Department of Pediatric Oncology and Hematology and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany;
3. Department of Pediatric Hematology and Oncology, University of Saarland, Homburg/Saar, Germany;
4. Department of Pediatric Hematology and Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and
5. Department of Pediatric Surgery, University of Munich, Munich, Germany