Several other mechanisms underlying increased tumor susceptibility to death after high-dose VitC treatment were recently reviewed (32) and include the increased expression of VitC transporters [SVCTs (33) and GLUTs (34)], as well as the decreased concentrations of antioxidant defenses (catalase and superoxide dismutase) and the enhanced cellular levels of prooxidant metal ions (18). Here, CAT is linked to neoplasm.