CAT and neoplasm: Furthermore, many reports have shown cellular changes resulting from oxidative stress produced by the generation of reactive oxygen intermediates (ROI) in tumor cells, which increases the cytotoxicity activity of the drugs [9]; the oxidative stress is a loss of balance between ROI production and intracellular antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (Gpx), and extracellular antioxidants.