Because of their safety and the fact that they are not perceived as "medici
ne," food-derived products are highly interesting for development as chemop
reventive agents that may find widespread, long-term use in populations at
normal risk. Numerous diet-derived agents are included among the >40 promis
ing agents and agent combinations that are being evaluated clinically as ch
emopreventive agents for major cancer targets including breast, prostate, c
olon and lung. Examples include green and black tea polyphenols, soy isofla
vones, Bowman-Birk soy protease inhibitor, curcumin, phenethyl isothiocyana
te, sulforaphane, lycopene, indole-3-carbinol, perillyl alcohol, vitamin D,
vitamin E, selenium and calcium. Many food-derived agents are extracts, co
ntaining multiple compounds or classes of compounds. For developing such ag
ents, the National Cancer Institute (NCI) has advocated codevelopment of a
single or a few putative active compounds that are contained in the food-de
rived agent. The active compounds provide mechanistic and pharmacologic dat
a that may be used to characterize the chemopreventive potential of the ext
ract, and these compounds may find use as chemopreventives in higher risk s
ubjects (patients with precancers or previous cancers). Other critical aspe
cts to developing the food-derived products are careful analysis and defini
tion of the extract to ensure reproducibility (e.g,, growth conditions, chr
omatographic characteristics or composition), and basic science studies to
confirm epidemiologic findings associating the food product with cancer pre
vention.