1. Center for Hematology and Regenerative Medicine, Karolinska Institutet, Department of Medicine, Karolinska University Hospital Huddinge, Stockholm, Sweden;
2. Haematopoietic Stem Cell Biology Laboratory, MRC Molecular Haematology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom;
3. Memorial Sloan Kettering Cancer Center, New York, NY; and
4. Division of Hematopathology, Department of Pathology, Karolinska University Hospital, Solna, Sweden