Chemoprevention refers to the use of nontoxic chemical substances to inhibit, reverse, or retard tumorigenesis. Numerous compounds derived from edible plants have been reported to interfere with a specific stage of the carcinogenic process. Some anti-inflammatory phytochemicals with cyclooxygenase-2 inhibitory activity have been found to exert chemopreventive properties by targeting intracellular signaling molecules (recently reviewed by Y.J. Surh, Nature Reviews Cancer, 3: 768-780, 2003). These include mitogen-activated protein kinases and transcription factors, such as NF-kappaB and AP-1.