TCF4/beta-catenin-IN-1 (Compound 8b) is an inhibitor of TCF4/beta-catenin, and induces apoptosis. TCF4/beta-catenin-IN-1 up-regulates p53, caspase-3, caspase-8, caspase-9 levels and Bax protein expression as well as down-regulates Bcl-2 protein expression. TCF4/beta-catenin-IN-1 can inhibit CYP3A4, CYP1A2, CYP2C19, and shows promising cytotoxic activity in cancer cells[1].