Fig. 2.

Schematic presentations of steps where chemopreventive agents can inhibit phase I enzyme induction. Chemopreventive agents can block the process of initiation by inhibiting xenobiotic induced transcriptional upregulation of phase I enzymes either by competing for receptor, inhibiting nuclear translocation of ligand and receptor complex or by inhibiting the binding of receptor ligand complex to specific promoter element. X = XAP2; 90 = heat shock protein 90; L = ligand (exogenous/endogenous); XRE = xenobiotic response element; C = chemopreventive agent.