FOXO3 and chronic myelogenous leukemia, BCR-ABL1 positive: Interestingly, Naka et al. showed that FOXO3a is essential for the maintenance of CML stem cells and suggested that TGF-β-mediated suppression of AKT activity resulted in increased levels of FOXO activity, positioning the role of TGF-β directly up-stream of the FOXO/BCL6 axis 16,19.