INS and melanoma: Melatonin reduces proliferation of several cancer cells in vitro, e.g., breast [62,63,64,65,66,67,68], melanoma [69,70] via several growth factor pathways (e.g., insulin, TOR, mitogen activated protein kinases, MAPK, epithelial growth factor, EGF [71,72,73,74,75,76]; reviewed in [61]) and regulates energy production via the insulin pathway, nutrient uptake and glycolysis (ib).