Growth response of various imatinib-resistant cell lines. Response to the combination of imatinib plus As₂O₃ (A) or imatinib plus decitabine (B). Fixed dose ratios of either combination were tested in MTT assays. Different curves indicate increasing doses of imatinib with the doses of the second combined drug depicted on the x-axis. Plotted is the percentage of growth inhibition of the untreated control (y-axis).