To model gene dose insufficiency by RNA interference (RNAi), we used a set of eight shRNA-expression vectors in the MDS/AML cell line SKM1, which reduced MYBL2 expression to 5–30% of the endogenous MYBL2 levels (Figure 2A), approximating the endogenous levels we had identified in CD34+ cells from patients (Figure 1B). The gene discussed is MYBL2; the disease is myelodysplastic syndrome.