To determine whether the antiproliferative activity of TKIs against Ph+ cells was mediated by reactivation of FOXO TFs, the CML cell line K562 was used to transiently over-express FOXO3a WT versus a constitutively active mutant form (insensitive to AKT phosphorylation) of FOXO3a (FOXO3a TM). This evidence concerns the gene FOXO3 and chronic myelogenous leukemia, BCR-ABL1 positive.