Green Tea Shows Promise in Preventing Pancreatic Cancer

Office of Cancer Complementary and Alternative Medicine
Division of Cancer Treatment and Diagnosis

Pancreatic cancer is highly resistant to current chemotherapy and radiotherapy treatments, and therefore, it presents one of the most difficult challenges for cancer clinicians and patients. These challenges provide researchers a strong mandate to develop better treatments than currently exist.

“We really need new [treatment] options,” said Rakesh Srivastava, Ph.D., at the University of Texas Health Science Center at Tyler. Pancreatic cancer is difficult to detect in its early stages, he explained. However, when researchers study the disease’s progression in the laboratory and in precancerous lesions, pancreatic intraepithelial neoplasias (PanINs), these conditions are usually much more treatable than the usually lethal cancer that will present itself clinically in later stages.

With funding from NCI*, Dr. Srivastava’s biochemistry lab is pursuing a lead that has powerful implications from epidemiological studies in China and Japan. A great deal of green tea is consumed daily in those regions, which also have the lowest rates of prostate and stomach cancer in the world. These populations may be benefiting from epigallocatechin-3-gallate (EGCG), a polyphenolic ingredient in green tea that previous laboratory research shows to be an effective anti-cancer component in that beverage.

Dr. Srivastava is trying to chart the mechanisms involved in green tea’s preventive effect, as well as trying to determine whether EGCG also works against PanINs. He and his colleagues will develop an oral dose of EGCG for mice and track the molecular impact of the compound on the animals’ early signs of pancreatic cancer.

One of the earliest genetic steps on the path to development of PanINs is mutations in the K-ras gene, “which we see highly expressed in more than 90 percent of invasive carcinomas,” Dr. Srivastava explained. Based on work from previous studies, the researchers are demonstrating how EGCG inhibits this particular altered metabolic pathway.

“EGCG’s effect on pancreatic cancer appears to be multi-pronged,” Dr. Srivastava added. Early-stage cancer cells proliferate by going through a series of cycles, but EGCG induces some specific inhibitors to interfere with this process. In addition, he has long been focused on the study of apoptosis, a form of programmed cell death, which cancer cells generally find ways to evade. He has found that EGCG blocks some of the cellular processes that inhibit apoptosis in cancer cells.

“What is promising about EGCG is the redundancy of its protective effects,” said Dr. Srivastava. “As a potential non-toxic, dietary preventive, green tea seems to carry a whole program of anti-cancer tools.”

OCCAM Program Director Dan Xi, Ph.D., commented, “This study is highly significant, because pancreatic adenocarcinoma still ranks as the most challenging of human malignancies, with an overall five-year survivor-ship of only three percent.”