CAT and cancer: In brief, looking into the mechanism of anticancer action, (1) secondary 1O2 is generated by the biochemical composition (containing NOX1, catalase, and SOD) of the tumor cell membrane; (2) secondary 1O2-mediated catalase inactivation occurs; (3) H2O2 flows into the cell through aquaporins; (4) intracellular ROS signaling is induced; and (5) mitochondrial apoptosis signaling occurs, resulting in cancer cell death [96].