HDAC9 and chronic myelogenous leukemia, BCR-ABL1 positive: The resistance to imatinib is a major problem in chronic myelogenous leukemia (CML) treatment, and recent studies have shown that by targeting telomerase expression using a dominant-negative form of the catalytic protein subunit of hTERT, or by the treatment with HDAC inhibitors, the risk of imatinib resistance may be reduced and the imatinib-induced apoptosis in leukemia cells may be enhanced, suggesting that antitelomerase strategies may be able to prevent, or at least delay the onset of such resistance (62,63).