Importantly, inhibition of GSK3 showed potential as a treatment for MLL-rearranged leukemia, as in a small-scale screen aiming to identify compounds that could induce the growth arrest of genetically defined subsets of leukemia cells, AML and ALL cell lines that expressed MLL-AF4 or MLL-AF5 showed enhanced sensitivity to GSK3-IX (also known as BIO), a GSK3 inhibitor that also targets cyclin-dependent kinases (CDKs) and has been extensively used for the maintenance of pluripotency in human and murine embryonic stem cells (ESCs) (Tseng et al., 2006; Wang et al., 2008). The gene discussed is KMT2A; the disease is acute myeloid leukemia.