In addition, it is interesting to note that H2O2 downregulates the levels of the antiapoptotic proteins FLICE-like inhibitory protein (FLIP) and X-linked inhibitor of apoptosis protein (XIAP) in imatinib-resistant K562 cells, which tends to promote CML cell apoptosis [48]. Here, XIAP is linked to chronic myelogenous leukemia, BCR-ABL1 positive.