Gunma Children's Medical Center - Department of Hematology/Oncology, Kyoto University - Department of Pathology and Tumor Biology, Gunma Children's Medical Center - Department of Hematology/Oncology, Gunma Children's Medical Center - Department of Hematology/Oncology, University of Tokyo, Institute of Medical Science, Human Genome Center, Laboratory of DNA Information, Kyoto University, Graduate School of Medicine, Department of Human Health Sciences, Nagoya University - Center for Advanced Medicine and Clinical Research, University of Tokyo, Institute of Medical Science, Human Genome Center, Laboratory of DNA Information, University of Tokyo, Institute of Medical Science, Human Genome Center, Laboratory of Sequence Analysis, Gunma Children's Medical Center - Department of Hematology/Oncology, Yokohama City University - Yokohama City University Hospital, National Research Institute for Child Health and Development - Department of Pediatric Hematology and Oncology Research, National Hospital Organization (NHO), Nagoya Medical Center, Clinical Research Center, Gunma Children's Medical Center - Department of Hematology/Oncology, National Center for Child Health and Development - Division of Leukemia and Lymphoma, Kyorin University, Faculty of Health Sciences, Department of Medical Technology, Okayama University, Graduate School of Medicine, Department of Pediatrics, Gunma Children's Medical Center - Department of Hematology/Oncology, National Hospital Organization (NHO), Nagoya Medical Center, Clinical Research Center, Shiga University of Medical Science - Department of Pediatrics, Kyoto University, Graduate School of Medicine, Department of Human Health Sciences, National Hospital Organization (NHO), Osaka National Hospital, Department of Pediatrics, University of Tokyo, Kyoto University - Department of Pathology and Tumor Biology and Gunma Children's Medical Center - Department of Hematology/Oncology