ABCG2 and cancer: Acacetin, O-methylated Apigenin, found in Robinia pseudoacacia, Turnera diffusa, and Betula pendula (87), exhibits anti-cancer effects in prostate cancer cells (88) and hepatocellular carcinoma (89) etc. Acacetin inhibits the activities and functions of both ABCB1 (90, 91) and ABCG2 (92).