BCR and chronic myelogenous leukemia, BCR-ABL1 positive: MiR-203 is significantly down-regulated in CML patients and the imposed expression of miR-203 is able to inhibit the proliferation of BCR/ABL cells positive for T315I mutation.   40  In CML cells, miR-31, miR-155 and miR-564 are down-regulated and down-regulation of them is dependent upon the activity of BCR-ABL.