Soja tegen borst- en prostaatkanker*
Uit twee studies blijkt dat een bioactieve stof in soja goed is tegen kanker. In de ene studie onder
prostaatkankerpatiënten blijkt dat dagelijkse inname van
genisteïne, een maand voorafgaande aan een operatie, uitzaaiingen kan tegengaan. Uit de andere studie blijkt dat vrouwen met voeding rijk aan het
isoflavoon genisteïne (dus niet uit supplementen) wel 30 tot 70% minder kans hebben op het krijgen van
borstkanker.
Prostate Cancer Spread May Be Halted By Soy
Northwestern Medicine researchers at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University have found that a new, nontoxic drug made from a chemical in soy could prevent the movement of cancer cells from the prostate to the rest of the body.
These findings were presented at the Ninth Annual American Association for Cancer Research Frontiers in Cancer Prevention Research Conference.
Genistein, a natural chemical found in soy, is being used in the lab of Raymond Bergan, M.D., the director of experimental therapeutics at the Lurie Cancer Center, to inhibit prostate cancer cells from becoming metastatic and spreading to other parts of the body. So far the cancer therapy drug has worked in preclinical animal studies and now shows benefits in humans with prostate
cancer.
A recent phase II randomized study of 38 men with localized prostate cancer found that genistein, when given once a day as a pill, one month prior to surgery, had beneficial effects on prostate cancer cells.
Researchers examined the cancer cells from the subjects' prostates after surgery and found that genistein increased the expression of genes that suppress the invasion of cancer cells and decreased the expression of genes that enhance
invasion.
"The first step is to see if the drug has the effect that you want on the cells and the prostate, and the answer is 'yes, it does,'" said Bergan, a professor of hematology and oncology at Northwestern University Feinberg School of Medicine and a physician at Northwestern Memorial
Hospital.
The next step is to conduct another phase II study to see if the drug can stop the cancer cells from moving out of the prostate and into the rest of the body, Bergan said. If confirmed, Bergan said this could be the first therapy for any cancer that is non-toxic and targets and inhibits cancer cell movement.
"All therapies designed to stop cancer cell movement that have been tested to date in humans have basically failed have because they have been ineffective or toxic," Bergan said. "If this drug can effectively stop prostate cancer from moving in the body, theoretically, a similar therapy could have the same effect on the cells of other cancers."
Funding from the National Institutes of Health supported this research.
Source: Northwestern University
High Isoflavone-Rich Soy Diet Lowers Invasive Breast Cancer Risk Significantly
Premenopausal women whose diet is high in isoflavone-rich soy products have a 30% lower risk of developing an invasive breast tumor compared to those with a very low intake, scientists from Roswell Park Cancer Institute explained at the 9th Annual American Association for Cancer Research (AACR) Frontiers in Cancer Prevention Research Conference.
Isoflavones belong to a class of usually naturally-occurring organic compounds that are related to the isoflavonoids. Many isoflavones act as phystoestrogens - nonsteroidal plant compounds that have estrogenic effects - in humans and other mammals. Isoflavones are antioxidants. They have been found to have cancer fighting qualities in several studies. Isoflavones can be found almost exclusively in the bean
(Fabaceae/Leguminosae) family.
Researcher Anne Weaver, said:
This study was unique in that we looked at specific subtypes of breast cancer, and found a suggestion that menopausal status may play a role in risk.
Weaver and team compared data on 611 healthy females and 683 diagnosed with breast cancer. They gathered information on their eating habits via a food frequency questionnaire which measured isoflavones dietary (not supplemental) intake. They divided isoflavones ingestion into three
groups.
The team discovered that the women who consumed the most isoflavones were about 30% less likely to develop an invasive breast tumor than those with very low consumption. The high isoflavones intake women also had a 60% lower risk of developing a Grade 1 tumor.
The scientists made the following observations related just to premenopausal women:
· A 30% lower risk of Stage 1 disease among the highest isoflavone consumers
· A 70% lower risk of developing a tumor bigger than 2cm among the highest isoflavone consumers
· A 60% lower risk of developing Stage 2 breast cancer among the highest isoflavone consumers
The lower risks listed above were only observed among the premenopausal women; not the postmenopausal ones.
Weaver and team stressed that further studies and confirmation are needed and that their findings are not authoritative.
Source: American Association for Cancer Research (Februari 2011)
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