Of special interest, proline catabolism involving proline dehydrogenase/proline oxidase (PRODH/POX) has been shown to be double-edged sword, which functions either as tumor suppressor to initiate ROS-mediated apoptosis, or as tumor survival factor through ATP production or ROS-induced autophagy depending on the tumor microenvironment7, 8, 9, 10, 11. This evidence concerns the gene PRODH and neoplasm.