TGFB1 and breast cancer: While the inhibitory effects of emodin on macrophage production of TGF-β1 can be explained by its suppression of M2-like macrophage polarization as we previously elucidated 16, 17, the mechanism by which emodin reduces TGF-β1 production in breast cancer cells and inhibits TGF-β1-induced breast cancer cell EMT likely involves blockage of TGFβR1 signaling.