Different from GMP-derived leukemias induced by Setbp1 and BCR/ABL [10], Hoxa9+BCR/ABL and Hoxa10+BCR/ABL leukemias are mostly monoclonal in origin (Supplementary Figure 6), suggesting that additional mutation(s) is likely required for the transformation in both cases. The gene discussed is HOXA9; the disease is leukemia.