Green Tea Found to Kill Leukemia Cells

Researchers using laboratory cell cultures have shown that a component of green tea known as epigallocatechin-3 gallate (EGCG) helps kill leukemia cells by interrupting the communication signals needed for them to survive.

The cells studied were from patients with B-cell chronic lymphocytic leukemia (CLL), which is most-often diagnosed in patients in their mid-to-late sixties. Currently, there is no cure, although chemotherapy is administered in severe cases. In the study, green tea's EGCG interrupted survival signals prompted leukemia cells to die in eight of 10 patient samples tested.

While the rationale has been to spare elderly patients exposure to toxic chemotherapy, new tests have improved the ability of doctors to identify early-stage patients who have a more aggressive form of the cancer. As a result, much CLL research is now focused on identifying which initial-stage patients should be treated earlier in the course of the disease, as reported in the February 2004 issue of the journal Blood.

The researchers focused on green tea because epidemiologic studies of cancer have shown that in parts of the world where green tea is consumed, the incidence of solid tumor cancers such as breast, lung, and gastrointestinal cancer is lower. Also, mouse-model testing of the cancer-prevention properties of green tea have shown they protect against solid tumors. In addition, the EGCG component of green tea has been shown in the laboratory to induce death in cancer cells from solid tumors. Research suggests that EGCG works by inhibiting a pathway in the leukemia cells related to angiogenesis.

"We're continuing to look for therapeutic agents that are nontoxic to the patient but kill cancer cells, and this finding with EGCG is an excellent start,” said Neil E. Kay, M.D., of the Mayo Clinic (Rochester, MN, USA).




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