The Ikzf1, Cbx5, Hmgb3, Ebf1 and Pax5 genes, all of which have been implicated in B-cell differentiation and associated with the progression of BCR-ABL1 B-ALL, were not affected by the loss of Klf5 in leukemic B-cell precursors (Supplementary Figure 4F–4J). The gene discussed is CBX5; the disease is precursor B-cell acute lymphoblastic leukemia.