FLT3 and leukemia: WT FLT3 is typically upregulated by MLL-fusions and is able to activate other pathways involved in cell growth and proliferation such as PI3K/AKT (Armstrong et al., 2002; Cauchy et al., 2015; Choudhary et al., 2005) One or more of these FLT3-activated growth signaling pathways may be essential for EOL-1 and MLL-PTD leukemia cell survival just as the STAT5A signaling pathway appears to be for FLT3-ITD leukemia.