In our preliminary screening for new antitumor agents from natural resources, HGK was found to have very good antitumor activity against MCF-7 breast tumor and Hep3b liver tumor cells with IC50 value being approximately 4.9 μg/mL, while no cytotoxicity at all against normal HUVEC cells even at 20 μg/mL. Here, MAP4K4 is linked to breast neoplasm.