Polyphenon E, a Green Tea Extract, May Prevent Breast Cancer
Researchers at Columbia University have found that an oral green tea catechin may have important health benefits.
--by Nina Lincoff
next time you walk into a coffee shop, rethink your drink order and get
a green tea. As beverages go, the health properties of green tea seem
endless. Numerous studies have already suggested that
eipgallocatechin-3-gallate (EGCG), a main component of green tea, has
anti-tumor properties that can treat or prevent breast cancer
Last year, at a Frontiers in Cancer Prevention Research meeting, researchers focused on the effects of green tea extract as a means of breast cancer prevention. They examined catechins, specifically Polyphenon E, which is a blend of many things, including EGCG. Catechins are flavanols, which occur naturally in plants and have strong antioxidant properties. Catechins have been linked to lower stroke rates, better heart function, and anti-aging effects when combined with exercise. And surprise, they’re found in green tea.
This week, researchers from the Columbia University Medical Center presented their secondary analysis of a study of 40 women who took doses (or placebos) of the oral green tea catechin Polyphenon E, which appears to inhibit pathways that are linked to tumor cell growth. There is some evidence, said study author Katherine Crew, MD, “that a green tea mixture, rather than pure EGCG, has greater anti-tumor activity.” However, the findings of the study aren’t clear-cut, and while Polyphenon E seems to inhibit tumor pathways, the ‘how’ is still unknown.
The Expert Take
After the secondary analysis, Crew said, her team “did not see a significant effect of the oral green tea extract, Polyphenon E, on either the oxidative stress or inflammatory biomarkers that we evaluated.” As a result, they widened the range of biomarkers observed and examined the effect of Polyphenon E on metabolic pathways.
“Our data suggests that Polyphenon E may have an effect on hepatocyte growth factor signaling, which is important in breast cancer development,” said Crew. Hepatocytes are liver cells that make up the majority of the organ. They synthesize and store proteins in addition to helping filter waste from the body.
These findings are also supported by clinical trials of Polyphenon E for treating and preventing prostate cancer. The next step in testing the efficacy of Polyphenon E, said Crew, is to conduct a larger randomized controlled trial in women who are at risk for developing breast cancer.
The Bottom Line
Once the correct biomarkers have been identified, researchers can most easily study the effects of Polyphenon E on breast cancer development. The two analyses thus far have been effective in narrowing down dosage and changing the focus of studies on Polyphenon E, but further research is required.
Source and Method
The presentation this week was the second analysis made on blood and urine samples taken from 40 women who had been given doses of Polyphenon E or a placebo twice a day for six months. In the secondary analysis, researchers examined different biomarkers to uncover the reasons behind the supposed tumor-inhibiting properties of green tea extract.
Although the reason for the reduction in hepatocyte growth factor is unknown, the women in the study who were given doses of Polyphenon E had nearly 10-times the green tea metabolites in their systems as those who took placebos after two-months.. After four months, however, the difference was no longer significant.
There is an ongoing trial of an oral green tea extract in 800 healthy postmenopausal women being conducted at the University of Minnesota, said Crew.