1. Department of Haematology/Oncology; Gunma Children's Medical Centre; Shibukawa Japan
2. Department of Paediatrics; Gunma University Graduate School of Medicine; Maebashi Japan
3. Division of Clinical Research Planning; Department of Development Strategy; Centre for Clinical Research and Development; National Centre for Child Health and Development; Tokyo Japan
4. Department of Paediatrics; Yokohama City University Hospital; Yokohama Japan
5. Division of Genetics; National Cancer Centre Research Institute; Tokyo Japan
6. Division of Leukaemia and Lymphoma; Children's Cancer Centre; National Centre for Child Health and Development; Tokyo Japan
7. Department of Paediatrics; Okayama University Hospital; Okayama Japan
8. Clinical Research Centre; National Hospital Organization Nagoya Medical Centre; Nagoya Japan
9. Department of Human Health Sciences; Kyoto University Graduate School of Medicine; Kyoto Japan
10. Department of Paediatrics; Shiga University of Medical Science; Ohtsu Japan
11. Department of Paediatrics; National Hospital Organization Osaka National Hospital; Osaka Japan