In vivo studies regarding the use of ZnO NPs as zinc sources or drug delivery systems in diabetes13–15 and cancer therapies16 have revealed their potential to interfere with zinc homeostasis and promote the bio-availability of therapeutic drugs or biomolecules (e.g., enhancing the efficiency of cancer therapy in animal models17,18, decreasing blood glucose by increasing the level of insulin in the blood of diabetic rats13). Here, INS is linked to cancer.