Main ingredient of green tea can prevent and stop tumor growth
Green tea’s popularity is soaring due to its numerous health benefits especially when it comes to treating cancer. Some research has indicated that green tea may have the ability to help in the prevention of certain cancers, yet the mechanisms behind the tea have not been fully understood.View slideshow: Green Tea and Cancer
Previous studies have suggested that eipgallocatechin-3-gallate (EGCG), the most important catechin may help certain types of cancer cells die. Exactly how has been somewhat of a mystery. New research suggests Polyphenol E a catechin that contains EEG appears to prevent VEGF (vascular endothelial growth factor, a single protein) and HGF (hepatocyte growth factor, cell signaling), both of which promote tumor cell growth, migration and invasion.
This new data was presented at the 11th Annual AACR International Conference on Frontiers in Cancer Prevention Research, held in Anaheim, Calif., Oct. 16-19, 2012. The presentation was made by Dr. Katherine D. Crew, MD, M.S., Assistant Professor of Medicine and Epidemiology at the NewYork-Presbyterian/Columbia University Medical Center.
According to Dr. Crew "Many preclinical studies have looked at epigallocatechin-3-gallate, or EGCG, which is one of the main components of green tea, and the various possible mechanisms of its action against cancer, but it is very difficult to do those same kinds of studies in humans. She adds that the study was small to be able to confirm green tea can prevent breast cancer but it may move researchers forward in order to understand “anti-tumor mechanisms.”
Last year a preliminary analysis was presented at Frontiers in Cancer Prevention Research meeting, researchers had concentrated their research of the effects of green tea extract as a method for breast cancer prevention.
In that study 40 women at random were assigned to 400 mg, 600 mg or 800 mg of Polyphenon E or to placebo twice daily for six months. During that time, researchers collected blood and urine samples from participants at baseline and at two, four and six months. Dr. Crew said that there was some evidence “that a green tea mixture, rather than pure EGCG, has greater anti-tumor activity.” She further adds the findings of the study were not clear-cut but Polyphenon E appeared to prevent tumor pathways but the “how “is unknown.
In a second analysis, researchers used blood and urine samples to examine biological endpoints (in clinical research, a disease, symptom, or sign that constitutes one of the target outcomes of the trial or its participants) such as inflammatory proteins, which might point to the mechanism of action behind green tea extract. Biomarker data were available for 34 of the 40 patients. Biomarkers are objective physical or biologic measures of health conditions.
The women that were assigned to the green tea extract had an average 10-fold increase in green tea metabolites compared with placebo. (Metabolites are substances produced by metabolism or by a metabolic process.) Researchers also found a significant reduction in hepatocyte growth factor levels at two months compared with women assigned to placebo. However, at the four-month and six-month follow-ups, the difference was no longer statistically significant.
Also noticed by researchers was the women who had been assigned the green tea extract had trend toward decreased total serum cholesterol and decreased vascular endothelial growth factor in women assigned to the extract.
Dr. Crew explains “Our data suggests that Polyphenon E may have an effect on hepatocyte growth factor signaling, which is important in breast cancer development.” These findings are also supported by clinical trials of Polyphenon E for treating and preventing prostate cancer.
According to Dr. Crew it is too early to recommend green tea extract to prevent breast cancer.
Currently Dr. Crew and research team are conducting several ongoing studies to examine the use of oral green tea extract in women who are at risk for developing breast cancer.
Other Evidence of Green Tea Extract
In an early Phase 1 study conducted at the Mayo Clinic had given green tea extract pills to people with early stage chronic lymphocytic leukemia (CLL). None of the participants had symptoms and would not normally be treated. Among those who had received the ECGC appeared to have less cancer cells after taking the ECGC compared to the number of cells at the start of study.
In 2006, an Italian study looked at men with prostate intraepithelial neoplasi, is condition in which some of the prostate’s epithelial cells look abnormal under the microscope, and sometimes progresses to prostate cancer. Half of the men in the study received green tea extract pills and the other half a placebo. The results of the study had shown that green tea extract reduced the risk of developing prostate cancer.
Numerous studies have demonstrated green tea extract appears to prevent cancer and stop tumor growth.
More information on green tea can be found online at Memorial Sloan-Kettering Cancer Center.