LEP and cancer: For example, leptin induces the expression of sterol regulatory element-binding proteins (SREBPs), including SREBP-1 and SREBP-2, master regulators of fatty acid and cholesterol synthesis, respectively, in breast cancer cells [89,90], which is opposite to the effects observed in non-transformed cells [91,92], suggesting that induction of SREBPs is a cancer cell-specific modulation of lipid metabolism by leptin.