but it follows that:
Genistein
Genistein is a phytochemical found in soybeans.[38] Soybeans contain a variety of phytochemicals, and in particular they are the only source with nutritionally significant amounts of one type of phytochemical called isoflavones. Foods that contain large amounts of soy are tofu, soy milk, and miso. In soy consuming populations, the concentrations of genistein average 0.28 µM, which is ten-fold higher than that seen in non-soy consuming populations.[39] Much interest has been shown recently in genistein as a chemopreventive agent in prostate cancer. Both epidemiological and migrant studies have demonstrated a correlation between increased isoflavone levels in the serum and urine of Asian men with decreased levels of prostate cancer.[40] Also, in a cross-national study for which data was available from 42 countries, soy products were identified as having a significant protective effect against prostate cancer.[41]
Genistein is a potent inhibitor of protein-tyrosine kinase and topoisomerase II, enzymes which are crucial to cellular proliferation. Genistein is also an inhibitor of angiogenesis and several steroid metabolizing enzymes, such as aromatase and 5 alpha-reductase.[42] A NCI-sponsored placebo-controlled clinical trial, Phase I Randomized Study of Genistein in Patients with Stage III or IV Prostate Cancer, has been underway since December 1999 to determine the safety and pharmacokinetics of genistein.