In chronic myeloid leukemia (CML) Ito et al. [12] showed the Nup98/HoxA9 fusion contributed to blast crisis through HoxA9 homeodomain binding to the Msi2 promoter resulting in gene over-expression, down-regulation of the Notch1 inhibitor Numb, and loss of the proliferation/differentiation equilibrium in hematopoietic stem cells (HSCs) [13]. The gene discussed is HOXA9; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.