NGF and cancer: For example, Lei et al. developed a siRNA-loaded gold nanocluster system (GNC-siRNA complex) to target the interactions between tumor cells andneuron against cancer via depleting the nerve growth factor (NGF) [251], a kind of neurotrophic factor that actively promote the growth of neurites and stimulate neurogenesis, contributing to the survival, proliferation, invasion, and metastasis of tumors [[252], [253], [254], [255]].