Mayo Clinic researchers have discovered that a component in green tea helps kill cells of the most common leukemia in the United States. The research using laboratory cell cultures shows that a component of green tea known as epigallocatechin-3-gallate (EGCG) helps kill leukemia cells by interrupting the communication signals they need to survive.

The leukemia cells studied were from patients with B-cell chronic lymphocytic leukemia (CLL) — most often diagnosed in patients in their mid- to-late 60s. Currently, there is no cure for CLL, though chemotherapy is administered in the most severe cases. The Mayo Clinic study, led by Neil E. Kay, MD, shows that green tea’s EGCG interrupted survival signals, prompting leukemia cells to die in eight of 10 patient samples tested in the laboratory.

Says Dr Kay: “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. Understanding this mechanism and getting these positive early results gives us a lot to work with in terms of offering patients with this disease more effective, easily tolerated therapies earlier.”

Since the 1970s, studies have shown that in parts of the world where green tea is consumed, the incidence of solid tumour cancers such as breast, lung and gastrointestinal cancers is lower. Also, mouse-model testing of green tea’s cancer-prevention properties has shown they protect against solid tumours. In the laboratory, the EGCG component of green tea has also been proven to induce death in cancer cells from solid tumours.

The Mayo Clinic research suggests EGCG works by inhibiting a pathway in the leukemia cells related to angiogenesis – the complex process that maintains nourishing blood flow to a biological structure, in this case a cancer cell.

Mayo Clinic, Mar 31, 2004