Polyphenols act as chemopreventive agents in prostate cancer due to their antioxidant or pro-oxidant effects (through reduction of ROS, increasing antioxidant enzyme activity, or inducing cytotoxicity), modulation of androgen receptors (inhibition of expression and function) or their transactivation of signaling pathways (PI3K, Akt, ERK1/2, FoxO, GSK-3β, RTK, etc). The gene discussed is MAPK3; the disease is prostate carcinoma.