Danish Cancer Society Research Center, Copenhagen, Denmark
Paediatric Department, Skejby Hospital, Aarhus, Denmark
Swedish Cancer Registry, National Board of Health and Welfare, Stockholm, Sweden
Division of Paediatric Oncology and Haematology, University Childrens Hospital, Lund, Sweden
Cancer Registry of Norway, Institute of Population-based Cancer Research, Oslo, Norway
Finnish Cancer Registry, Cancer Society of Finland, Helsinki, Finland
Turku University Hospital, Department of Paediatrics, Division of Pedriatric Hematology and Oncology, Turku Finland
Icelandic Cancer Registry, Icelandic Cancer Society, Reykjavik, Iceland
Department of Cancer Epidemiology, Lund University, Lund, Sweden
Paediatric and Adolescent Medicine, Juliane Marie Center, Rigshospitalet