DRD2 and liver cancer: In liver cancer, fisetin, which can act as a D2R agonist, inhibited TGF-β1 secretion and reduced epithelial mesenchymal transition not only by downregulating VEGFR1, p-ERK1/2, p38 and pJNK signaling pathways, but also by inducing apoptosis of liver cancer cells by activating caspase-3, indicating that DA may inhibit the growth of liver cancer [61].