We then examine the effect of Necdin deficiency on HSPC proliferation and found that Necdin null HSPCs expressing AML1-ETO9a show decreased proliferation compared to wild type HSPCs (Figures 4E and 4F), indicating that Necdin is important for the proliferation of HSPCs expressing AML-ETO9a. Here, RUNX1 is linked to acute myeloid leukemia.