While IGFBP2 is expressed at high levels by M3 t(15:17) APL cells that produce a fusion protein promyelocytic leukemia-retinoic acid receptor α (PML-RARA), the physiologic PML-RARA expression from the mouse pml locus rarely causes leukemia development[36]. This evidence concerns the gene IGFBP2 and acute promyelocytic leukemia.