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Green Tea Compound Slowed Chronic Lymphocytic Leukemia
Researchers caution finding was preliminary, effect seen only in early stages of disease A key component of green tea has shown promise as a non-toxic treatment for chronic lymphocytic leukemia (CLL). Researchers at the Mayo Clinic are now in the second phase of trials with early-stage, asymptomatic patients to explore the potential of epigallocatechin gallate (EGCG) to strike a blow against this type of leukemia. "The benefits we have seen in most CLL patients who use the chemical suggest that it has modest clinical activity and may be useful for stabilizing this form of leukemia, potentially slowing it down," lead author Dr. Tait Shanafelt, a Mayo Clinic hematologist, said in a news release. Shanafelt's team is slated to present its findings Monday at the American Society of Clinical Oncology annual meeting, in Chicago. The latest research builds on earlier Mayo lab work from eight years ago, during which EGCG's potential to curtail the survival of CLL leukemia cells was first noted. The current trial marks the first time this green tea extract has been studied in actual patients as a treatment option for an illness that is described as a hybrid between leukemia and lymphoma. A total of 42 CLL patients were involved in the phase 2 trial. All were at such an early point in their illness that they were not taking any other treatment. Nearly one-third showed a 20 percent or greater drop in their leukemia cell count after being treated with EGCG. What's more, almost 70 percent of the patients who had enlarged lymph nodes saw their node size cut in half or more following treatment, the researchers found. Yet despite the encouraging findings, the study authors cautioned that EGCG would not ultimately replace chemotherapy. And they expressed hesitancy with respect to any current patient use of the compound while research is ongoing. "Without a phase 3 clinical trial, we cannot make a recommendation that EGCG be used by CLL patients," co-author Dr. Neil Kay, a hematology researcher, said in a news release. "But those who want to take supplements should consult with their oncologists and need to receive appropriate monitoring using laboratory tests." SOURCE: American Society of Clinical Oncology
Green tea reduces risk of blood cancers by 42 percent
(Natural News) A Japanese green tea study has determined impressive results regarding the reduction of blood and lymph cancers. Tohoku University researchers found a 42 percent reduction for blood cancers and 48 percent reduction for lymph cancers with high green tea consumption. In a study published in the September issue of the American Journal of Epidemiology, Dr. Toru Naganuma of Tohoku University School of Medicine in Senda and colleagues reported that drinking at least five daily cups of green tea was found to slash the risk of blood cancers by 42% and lymph system cancers by 48%. What's more, these enormous reductions in cancer were consistent in both men and women and in people with various body mass sizes. While Dr. Naganuma was looking at blood and lymph cancer rates, another research team in the Division of Epidemiology in Tohoku University's Department of Public Health and Forensic Medicine was also searching the Ohsaki National Health Insurance Cohort Study and they discovered yet another link between green tea and cancer prevention. Their study, published in the September issue of the journal Cancer Causes and Control found that green tea consumption was inversely associated with the incidence of liver cancer. The study documented that the more green tea consumed, the more the risk plummeted -- five cups or more offered the most protection from liver malignancies. All of the research is based on findings from the huge Ohsaki National Health Insurance Cohort Study in Japan which involved 41,761 Japanese adults between 40 and 79 years of age. None of the research subjects had a history of cancer when the study started and their diets, along with other lifestyle factors and any health problems they developed, were followed for about ten years.The epidemiological studies (statistical observations over time) of Japan have been bolstered with western clinical application and lab studies that revealed interesting observations. For example, the Mayo Clinic of Minnesota fed leukemia patients large doses of GTE's (green tea extracts) and discovered immediate benefits in their patients. However, the doctors consider GTE's a helpful adjunct to orthodox cancer treatments. They declined the notion of using GTE's exclusively or in conjunction with other natural cancer treatments. Researchers in Spain and England isolated the mechanics of green tea's inhibition of cancer cells. Their research was published back in the March 2005 issue of Cancer Research. They found that ECGC, an extremely abundant catechin in green teas inhibits the enzyme dihydrofolate reductase (DHFR). Catechins are active polyphenolic antioxidant metabolites in green tea. The DHFR enzymes they inhibit are needed by cancer cells to proliferate. Upon closer scrutiny of green tea ECGC, they determined that its molecular structure closely resembles that of the cancer drug methotrexate used in chemotherapy. The good news is that the binding properties of ECGC is not as intense as the drug methotrexate. Therefore, the side effects of green tea are minimal. But there is one situation where green tea's ECGC binding to DHFR can be detrimental: ECGC binding to DHFR can inhibit the folic acid needed by women pregnant in their first trimester. This situation has been shown to increase the risk of her child being born with spina bifida or other fetal neurological disorders. Because of this, it is recommended that women curb their green tea consumption just prior to pregnancy and during the first trimester.
Fight Leukemia with Green Tea
Now, a new study supports the use of green tea against leukemia, this time from the prestigious Harvard School of Public Health. The study compared people who had leukemia with those who did not, and found that people aged 16 to 29 who drank the most green tea had less than half the risk of having leukemia as those who drank the least. Those drinking the most tea consumed 550 mg or more of EGCG-rich catechins a day, the equivalent of about 5 ½ cups. (Kuo, YC, et al. Cancer Causes Control. 2008 Aug 28.)
Green Tea & Leukemia: Mayo Clinic Study
Preliminary research released by the Mayo Clinic in Dec 2005 showed that four patients with CLL appeared to have an improvement in the clinical state of their disease after beginning a regimen of products containing epigallocatechin gallate (EGCG), an extract of green tea sold in drugstores. The Mayo Clinic scientists say they are building on data they had previously gathered showing that EGCG kills leukemia cells from patients with CLL in the test tube by interrupting the communication signals they need to survive. The Mayo Clinic studied the impact of epigallocatechin-3-gallate (EGCG), a known receptor tyrosine kinase (RTK) inhibitor, on VEGF receptor status. Chronic lymphocytic leukemia (CLL) cells synthesize and release vascular endothelial growth factor (VEGF) under normoxic and hypoxic conditions. EGCG significantly increased apoptosis/cell death in 8 of 10 CLL samples measured by annexin V/propidium iodide (PI) staining. EGCG (3-25 microg/mL) suppressed VEGF-R1 and VEGF-R2 phosphorylation, albeit incompletely. Thus, these results suggest that VEGF signaling regulates survival signals in CLL cells and that interruption of this autocrine pathway results in caspase activation and subsequent leukemic cell death. "The experience of these individuals provides some suggestion that our previously published laboratory findings may actually translate into clinical effects for patients with this disease," said lead study author Tait Shanafelt, a Mayo Clinic hematologist. The latest findings are published online in Leukemia Research. CLL is a blood and bone-marrow cancer that affects 8,000 to 15,000 new patients each year in the United States, the researchers said.
Green Tea & Leukemia
Yet another study found that green tea extract is a potent nucleoside transport inhibitor, interfering with tumor cells' repair of DNA after chemotherapy. Thus green tea extract "markedly potentiated" the effectiveness of chemotherapy. These findings suggest that epigallocatechin gallate and green tea extract could be used as a nontoxic adjuvant therapy for leukemia. It would also be interesting to examine how green tea polyphenols synergize with such established anti-leukemic alternative treatments as retinoic acid, Vitamin D3, DMSO, curcumin and esculetin.
Green Tea and Leukemia - Moffitt Study
Leukemia is yet another disease where green tea may prove effective as an adjuvant therapy for treatment. The particularly bioactive catechins in green tea, epigallocatechin gallate, was found to inhibit the proliferation of human and mouse leukemic cells in vitro. Leukemia is yet another disease where green tea may prove effective as an adjuvant therapy for treatment. The particularly bioactive catechins in green tea, epigallocatechin gallate, was found to inhibit the proliferation of human and mouse leukemic cells in vitro. The Drug Discovery Program, of the H. Lee Moffitt Cancer Center and Research Institute reported that the tea polyphenol (-)-epigallocatechin (EGC) inhibits DNA replication in three leukemia cancer cell lines, Jurkat T, HL-60 and K562. Among all the tested tea polyphenols, EGC was found to be the most potent in accumulation of S phase cells and inhibition of the S-G2 progression. In addition, EGC-mediated inhibition of S phase progression results in induction of apoptosis, as determined by sub-G1 cell population, breakage of endonuclear DNA, cleavage of poly(ADP-ribose) polymerase and loss of cell viability. Even at the lower concentration, DNA synthesis by leukemic cells was reduced by more than 50%, while normal cells were unharmed. Another study, using the leukemic blast cells from patients with acute myeloblastic leukemia, a particularly aggressive and often deadly form of leukemia, found that epigallocatechin gallate inhibited the effect of tumor necrosis factor alpha and other growth factors. Consistent with the putative role of green tea in cancer prevention, tea polyphenols have been shown to inhibit tumor cell proliferation by inducing G1 or G2/M cell cycle arrests, also documented is their ability to induce apoptosis (programmed cell death).
Green Tea & Leukemia: Animal Bone Marrow Study
studied the impact of epigallocatechin-3-gallate (EGCG), a known receptor tyrosine kinase (RTK) inhibitor, on VEGF receptor status. Chronic lymphocytic leukemia (CLL) cells synthesize and release vascular endothelial growth factor (VEGF) under normoxic and hypoxic conditions. EGCG significantly increased apoptosis/cell death in 8 of 10 CLL samples measured by annexin V/propidium iodide (PI) staining. EGCG (3-25 microg/mL) suppressed VEGF-R1 and VEGF-R2 phosphorylation, albeit incompletely. Thus, these results suggest that VEGF signaling regulates survival signals in CLL cells and that interruption of this autocrine pathway results in caspase activation and subsequent leukemic cell death.
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