MT-CYB and chronic myelogenous leukemia, BCR-ABL1 positive: We investigated the effect of doxorubicin (DOX), a DNA-damaging anticancer drug, on apoptosis and the expression of the mitochondrial NADH dehydrogenase 3 (MT-ND3) and cytochrome b (MT-CYB) in model CML cells showing imatinib resistance caused by Y253H mutation in the BCR-ABL1 gene (253) or culturing imatinib-sensitive (S) cells in increasing concentrations of imatinib (AR).