CAT and pancreatic neoplasm: Part of the mechanism by which exosomes confer chemo-resistance in pancreatic cancer cells has been revealed and involves the upregulation of two ROS detoxifying enzymes, the superoxide dismutase 2 (SOD2) and catalase (CAT), and the miR-155-mediated downregulation of gemcitabine-metabolizing enzyme, DCK [68].