Furthermore, enforced expression of another MLL fusion protein, MLL-AF9, and other non-MLL leukemia drivers, including AML1-ETO, MYC, and NRAS in primary HSPCs, show that the upregulation of Igf2bp3 is specific to MLL-Af4 (Supplementary Fig. 1f). This evidence concerns the gene AFF1 and leukemia.