CD34 and myelodysplastic syndrome: It has previously been reported that genome-wide DNA methylation profiles of bone marrow CD34+ and CD34− cells are very similar in MDS.12 Consistent with this, we determined that the total DNA methylation levels by AZA-MS were similar in an MDS patient (mean in CD34+ cells=4.8% mean in CD34− cells=5.1% P-value=0.39, Supplementary Figure 5f).