By analyzing Annexin V expression on cell surface, we found that IM/BOR and IM/PSI induced apoptosis at ratios significantly higher than those in each mono-treatment in K562 (Figure 6A), primary CD34+ cells from CML patients (Figure 6B) and BCR-ABL/32D cells (data not shown). Here, ABL1 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.