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Friday, August 29, 1997

Researchers to test green tea as cancer fighter

HOUSTON (AP) -- Cancer experts at the Texas Medical Center hope to prove with a new study that green tea helps to fight and prevent the disease.

Tests on laboratory animals and studies of populations in Japan and China, where green tea is popular, support the idea that it can postpone or even prevent cancer development, said Dr. Waun Ki Hong of the University of Texas M.D. Anderson Cancer Center.

"The epidemiologic studies are interesting," said Hong, chairman of the thoracic and head/neck cancer medical oncology department and a pioneer in the use of chemicals to prevent cancer.

"In Japan, people who drink green tea have a delayed occurrence of cancer compared to those who don't drink it."

A study in Shanghai, China, cited in a recent issue of the Nutrition Research Newsletter, showed green tea drinkers statistically had significant reductions in the risk of developing rectal and pancreatic cancers.

While there were numerical reductions seen in colon cancer, they were not statistically significant, the researchers reported.

A recent study in the scientific journal Nature showed that a component of green tea called epigallocatechin gallate, or EGCG, binds an enzyme called urokinase, thus preventing it from carrying out its mission. Urokinase is an enzyme that has been shown to have a connection with cancer metastasis, Hong said.

The family of chemicals to which the EGCG belongs seems to have some anti-tumor effect, said Dr. Katherine Pisters, the assistant professor at Anderson who will lead the study.

The first study, planned for 30 patients with advanced cancer of the lung, breast, prostate, ovaries or head and neck, will determine if the material is safe and how much patients can tolerate, Dr. Pisters said.

The patients will receive capsules of green tea equal to six or seven cups, Hong said. Doctors will escalate the dose if they don't see any side effects.

Using capsules makes it easier to determine how much tea and chemicals each patient is receiving.

Hong believes the capsules will prove more effective in preventing cancer than in treating it.

Dr. Pisters said patients aren't given false hopes.

"We tell them we have a new and interesting compound that we are testing. We say it might be a reasonable thing for them to try," she said.

She hopes the study, which is being conducted with Memorial Sloan-Kettering Cancer Institute in New York, will be completed within two years.

It is being funded by ITO-EN Central Research Institute in Shizuoka, Japan. ITO-EN is the largest manufacturer of green tea in Japan.