Protein in Soy Traps Prostate Cancer
Genistein Stops Prostate Cancer's Spread in Mice; Human Trials Under Way
March 14, 2008 -- Dietary levels of genistein, a soy protein, stopped the
spread of prostate
cancer in mouse studies, Northwestern University researchers report.
Men who live in countries with high soy consumption are less likely to die
of prostate cancer than are men in the U.S. and Europe. Genistein, a protein
from soybeans, keeps prostate cancer cells from spreading in test-tube
Now a study led by Raymond C. Bergen, MD, director of experimental
therapeutics for the Robert H. Lurie Comprehensive Cancer Center at
Northwestern University, shows that genistein fights human prostate cancers
implanted in living animals.
The soy compound doesn't make prostate cancer go away. It doesn't even make
prostate tumors smaller. But it does keep the cancer cells from spreading
through the body. Like some other cancers, prostate cancer is not deadly unless
it spreads through the body -- a process known as cancer metastasis.
"These impressive results give us hope that genistein might show some
effect in preventing the spread of prostate cancer in patients," Bergen
says in a news release. "Now we have all the preclinical studies we need to
suggest genistein might be a very promising chemopreventive drug."
A 2003 human study showed that when men with prostate cancer took genistein
preparations, their blood levels of genistein reached concentrations that had
anticancer effects in the test tube. These are the same genistein blood levels
that protected mice in the current study.
Bergan and colleagues note that a larger clinical trial of genistein is
under way. Other researchers are studying the compound in patients with breast cancer, kidney cancer,
endometrial cancer, pancreatic
cancer, and melanoma.
Bergan and colleagues report their findings in the March 15 issue of