In these experiments, the murine MDR1-transfected variant MPAM-26 and the human P-gp+ transfected lines MPAHS-1-10, MPAHS-1-300 and MPAHS-DOX150 were found to have a four to five fold increased sensitivity to LAK CML in comparison to the drug sensitive parent line MDA-MB-231. Here, ABCB1 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.