A compound found in soybeans almost completely prevented the spread of human prostate cancer in mice, according to a study published in the March 15 issue of Cancer
Research, a journal of the American Association for Cancer Research.

Feeding mice genistein, an antioxidant found in soy, decreased metastasis of prostate cancer to the lungs by 96 percent compared with mice that were not fed genistein. According to the study’s researchers the amount of genistein that was
fed to the mice was no higher than what a human would eat in a soybean-rich diet.

“These impressive results give us hope that genistein might show
some effect in preventing the spread of prostate cancer in
patients,” said the study’s senior investigator, Raymond C. Bergan,
MD, director of experimental therapeutics for the Robert H. Lurie
Comprehensive Cancer Center of Northwestern University.

“Diet can affect cancer and it doesn’t do it by magic,” Bergan
said. “Certain chemicals have beneficial effects and now we have all
the preclinical studies we need to suggest genistein might be a very
promising chemopreventive drug.”

Prior to this study Bergan had demonstrated in prostate cancer
cell cultures that genistein inhibited the detachment of cancer cells
from a primary prostate tumor. Genisten blocks the activation of certain molecules which regulate protein pathways. These pathways loosen cancer cells
from a tumor and push them to migrate to distant sites .”When genisten is introduced into a cell culture, you can actually see cells flatten themselves in order to spread out and adhere to nearby cells,” said Bergen.

This study, which was done at Northwestern University, was the first to find that genistein can stop prostate cancer metastasis in a living organism.

Genistein did not reduce the size of tumors in the prostate, but it did stop lung
metastasis almost completely. The experiment was replicated and found
the same result.

Epidemiologic studies have shown that men who eat soy are at reduced risk of prostate cancer death. However, these results are associative and do not prove any causation. However, this study strongly points the way for a quick start of a clinical trial to see if these results will hold up in humans and if there is a causative relationship between inhibiting prostate cancer tumor cell migration and genisten.

In the mean time increasing your soy consumption might not be a bad idea.

Joel T Nowak MA, MSW