Green Tea may stop the formation of colon cancer in its tracks.

August 09, 2007

Almost one-million new cases of colon cancer are diagnosed globally each year with very close to 500,000 deaths annually. In this new study, scientists at the Medical University of South Carolina show that Green Tea may stop the growth of colon tumors in their infancy according to the results of their animal study. However, drinking normal amounts of brewed green tea is not likely to inhibit the progress of any large polyps or large existing cancers that occur before tea administration.

ApcMin mice are used in colon cancer research. When drug manufacturers test to see if a drug inhibits colon cancer or if chemotherapy shrinks colon cancer they commonly employ these mice. These mice commonly develop 100 tumors in their intestinal tract. The researchers treated or rather poisoned the mice with azoxymethane; a chemical that selectively and dependably causes colon cancer. At 8-weeks of age the mice were divided into two groups, one group received water as a placebo and the other group of these otherwise doomed mice received a green tea solution (0.6%). The Green Tea significantly inhibited the formation of new tumors in the colon, but had no effect on existing larger tumors. The scientists explain that brewing green tea affects many early biomarkers of cancer and this affects smaller tumors but that brewing regular levels of Green Tea is not enough to affect other factors such as the COX-2 enzyme in colon cancer and that higher potencies seem to be needed for these other cancer factors. This also shows that brewed Green Tea protects us from developing colon cancer in novel ways. This study is published in the new issue of the journal Carcinogenesis.

Nude mice lack an immune system and have no defense against the growth and spread of orthotopic human cancers (orthotopic is the grafting of a human cancer onto the affected site in an animal and therefore lung cancer would be implanted surgically into the appropriate area of the lung and colon cancer would be inserted surgically into the typically affected site in the colon).

When colon cancer metastasizes it usually affects the liver and lungs. Once this occurs the prognosis is poor.

In this study, nude mice had human colon cancer grafted into their colon. Growth of the colon tumors was inhibited by EGCG. EGCG at higher concentrations also inhibited the metastasis of the colon cancer to the lungs and liver to varying degrees depending on the concentration of EGCG. The study is published in the July 2007 issue of the journal Pharmacology.