BMNZs for cancer treatments can be generally categorized into two categories based on their ROS generation mechanism, utilizing tumor microenvironment characteristics such as excessive H2O2 and glucose: (1) BMNZs that produce ROS through POD- and OXD-like catalysis, and (2) BMNZs that yield ROS in the presence of photosensitizers and CAT mimetics in which O2 is produced to increase photodynamic therapy efficiency. The gene discussed is CAT; the disease is cancer.