The balance between oxidation and reduction is vital to the normal functioning of a cell and abnormal redox states have been shown to confer resistance to cytotoxic agents in cancer chemotherapy.38 The reducing capacity of a cell is determined by the expression of reducing agents/enzymes including glutathione (GSH), glutathione peroxidase (GSHPx), catalase and superoxide dismutase (SOD), relative to the oxidative load. The gene discussed is SOD1; the disease is cancer.