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) [epi-gallo-cat-ekin-3-gal-ate] helps kill leukemia cells by interrupting the communication signals they need to survive. The findings are reported in an early electronic article in the journal Blood http://www.bloodjournal.org/cgi/reprint/2003-08-2763v1.
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, M.D., 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.”
About the Leukemia called CLL
CLL affects individuals differently in the pace at which it progresses. Some patients may live with it for decades and not require treatment, while others need immediate treatment, and some die within months despite therapy.
Because the course of the CLL is so individualistic and unpredictable, physicians have historically adopted an attitude of “watchful waiting” with early-stage CLL patients. This rationale -- to spare elderly patients exposure to toxic chemotherapy -- has been challenged recently as new tests have improved physicians’ ability to identify early stage patients who have a more aggressive form of the cancer.
As a result, much CLL research is focused on identifying which initial-stage patients should be treated earlier in the course of their disease -- the topic of another recent article by Mayo Clinic researchers (Blood, Feb 2004; 103: 1202 - 1210.)