Ikeda et al. revealed that CEP could potently enhance the sensitivity to cytotoxic agents such as doxorubicin in K562 leukemia cells, not only via a reversal of ABCB1- mediated multi-drug resistance (MDR) but also increasing the accumulation of doxorubicin in nuclei (Ikeda et al., 2005). This evidence concerns the gene ABCB1 and leukemia.