By using doxorubicin-sensitive and resistant K562 CML cells, Hui et al. [200, 201] have demonstrated that resistance to doxorubicin is associated with increased activity of PI3K/Akt, through a mechanism of feedback and with the ABCB1 gene induction. This evidence concerns the gene ABCB1 and chronic myelogenous leukemia, BCR-ABL1 positive.