CAT and cancer: Cyclophosphamide (CPA), an immunosuppressant employed in cancer therapy, paradoxically exacerbates oxidative stress through ROS overproduction and the downregulation of antioxidant enzymes—including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px)—in the spleen and thyroid tissues (Xu and Zhang, 2015; Li et al., 2017).