Wednesday, July 01, 2009

Green Tea Has Role in Prostate Cancer Prevention

A clinical trial whose results were published this month concluded that green tea has a potential role in the treatment or prevention of prostate cancer.

A team of researchers from the Louisiana State University Health Sciences Center and Overton Brooks VA Medical Center in Shreveport, La., conducted the study, which sought to determine whether high doses of the polyphenol found in green tea could reduce the levels of serum biomarkers associated with poor prognosis in prostate cancer patients.

The study was based on previous work indicating that epigallocatechin-3-gallate (EGCG), the polyphenol in green tea, has possible benefits for patients with prostate cancer, which leads to the death of some 27,000 men in the United States each year.

Twenty-six men ages 18 to 75 took 800 milligrams of EGCG daily over an average of six weeks. The EGCG was contained in Polyphenon E pills, and the patients all were scheduled to have their prostates removed.

Before and after the surgery, researchers measured the levels of several tissue markers that have been shown to indicate the worsening of prostate cancer. They found that, "men diagnosed with prostate cancer who take 1.3 grams daily of green tea catechins (800 milligrams EGCG) show a significant reduction in" several of these markers, stated a report published in the June 19 issue of Cancer Prevention Research.

Further in vitro study of cells also indicated that EGCG blocked the production of two of the biomarkers – hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF) – in "at least two different prostate cancer-associated fibroblast cell lines." This is significant because HGF has been demonstrated in other research to promote cancer progression, the report noted, and lower levels of VEGF is predicted to increase a patient's overall survival time.

The study also looked at the possible detrimental effects on the liver of the high doses of EGCG, and found none.

The report concluded, "These data support a potential role for Polyphenon E in the treatment or prevention of prostate cancer and suggest that these findings should be verified by larger, placebo-controlled clinical trials."

Dr. James Cardelli, professor of microbiology and immunology and co-director of the LSU Cancer Center said, "The work will continue, and in fact we have opened a clinical trial to begin to determine if tea extracts can increase overall survival of lung cancer patients when combined with the targeted agent Tarceva. A lot of work still needs to be done."

Friday, 26 June 2009
by Heidi Kyser

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