Nevertheless, analogous to iron, heme is also toxic when in excess.[55] Copper has long been found to regulate heme homeostasis and Heme Oxygenase 1 (HMOX1, encoding an important enzyme for heme metabolism and possesses multiple functions in cancer and is usually stress‐induced), a copper‐responsive gene.[56] Recent investigations have demonstrated that both copper ionophore disulfiram (DSF)‐Cu and copper nano‐delivery drugs/nanozymes could induce the expression of HMOX1. Here, HMOX1 is linked to cancer.