1. Center for Life Sciences, Harvard Medical School, and Harvard Stem Cell Institute, Boston, MA;
2. Hematology Division of the Department of Internal Medicine, Centre for Cell Based Therapy, Medical School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil;
3. Dana-Farber Cancer Institute, Boston, MA;
4. Section on Developmental and Stem Cell Biology, Joslin Diabetes Center, Department of Stem Cell and Regenerative Biology, Harvard University, and Harvard Stem Cell Institute, Boston, MA; and
5. Cancer Science Institute, National University of Singapore, Singapore