The anthracycline class antibiotic doxorubicin (DOX) has been widely used for the treatment of a range of cancers.17 In aerobic conditions, DOX can elicit the production of superoxide radicals (O2•−) by activating the nicotinamide adenine dinucleotide phosphate (NADPH) oxidases and further catalyzing the reaction of NADPH and oxygen (O2).18 O2•− can induce cancer cell death via oxidative damage to cellular components, which also increases the sensitivity of tumor cells to DOX.19 Alternatively, superoxide dismutase (SOD) can convert the O2•− to H2O2,20 which is the substrate of CDT. The gene discussed is FMO5; the disease is cancer.