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Green Tea & Cancer - Read what noted Oncologist Dr. Mitchell Gaynor's has to say about green tea. Select from our updated articles database for specific cancers:

Green Tea & Tumor Growth (tNOX)


Date: 01-01-2003
A study done at Purdue University and presented at the 1998 meeting of the American Society for Cell Biology, discovered another major mechanism. The authors, the husband and wife team of Dorothy and James Morre, claim that the main tumor-inhibitory mechanism of green tea may stem from its ability to interfere with the enzyme quinol oxidase, generally referred to as NOX. This enzyme is required for growth by both normal and malignant cells. While normal cells express NOX only when dividing, tumor cells express it all the time. The tumor form of the enzyme is called t-NOX, or tumor-associated NOX. Drugs that inhibit tNOX also inhibit tumor growth. While both black and green tea infusions inhibited tNOX in various cancer lines, green tea was able to achieve these results at much greater dilutions, indicating higher concentrations of the active compound or compounds. By selectively testing for active compounds, the authors of the study concluded that epigallocatechin gallate was the active agent responsible for inhibiting tNOX - while sparing the NOX of healthy cells. Dr. Dorothy Morre stated, "In the presence of epigallocatechin gallate, the cancer cells literally failed to grow or enlarge after division. Then, presumably because they failed to reach the minimum size needed to divide, they underwent programmed cell death, or apoptosis." While the inhibition of ateliers. and of tNOX may be the chief anti-carcinogenic mechanisms of green tea polyphenols, or at least two very important ones, there is little doubt that green tea catechins act along several different pathways and interact with a variety of enzymes to produce their anti-cancer effects. It should also be noted that green tea lowers serum glucose and consequently insulin (this will be discussed in detail in the second article on green tea). Since elevated insulin is a potent growth factor for many kinds of tumors, as well as a pro-inflammatory and immunosuppressive hormone, the lowering of insulin in itself should help prevent cancer or, in cases of existing cancer, slow down its growth.
References: Life Extension Magazine and other studies added.

Asano Y, Okamura S et al. Effect of epigallocatechin gallate on leukemic blastcells from patients with acute myeloblastic leukemia. Life Sci 1997; 60:135-42 Berger SJ, et al. Green tea constituent (--)-epigallocatechin-3-gallate inhibits topoisomerase I activity in human colon carcinoma cells. Biochem Biophys Res Commun 2001;288:101-5.
Challa A et al. Interactive suppression of aberrant crypt foci induced by azoxymethane in rat colon by phytic acid and green tea. Carcinogenesis 1997; 10:2023-26
Chen ZP, et al. Green tea epigallocatechin gallate shows a pronounced growth inhibitory effect on cancerous cells but not on their normal counterparts. Cancer Lett 1998; 129:173-79
Chung FL et al. Inhibition of lung carcinogenesis by black tea in Fischer rats treated with a tobacco-specific carcinogen: Caffeine as an important constituent. Cancer Res 1998;58:4096-4101
Deng ZY, Tao BY, et al. Effect of green tea and black tea on blood glucose, triglycerides, and antioxidants in aged rats. J Agricult Food Chem 1998;46:3875-78
Francheschi S et al. Influence of food groups and food diversity on breast cancer risk in Italy. Int J Cancer 1995; 63:785-89
Goodwin Sarah Federation of American Societies for Experimental Biology 18-Apr-2004
Hamilton-Miller JM. Anti-cariogenic properties of tea (Camellia sinensis). J Med Microbiol 2001;50:299-302
Hara Y. Influence of tea catechins on the digestive tract. J Cel Biochem 1997; Suppl 27: 52-58
Hibasami H et al. Induction of apoptosis in human stomach cancer cells by green tea catechins. Oncol Repetition 1998; 5:527-29
Hirose M et al. Inhibition of mammary gland carcinogenesis by green tea catechins and other naturally occurring antioxidants in female Sprague-Dawley rats pretreated with MDBA. Cancer Lett 1994; 83:149-56
Hong J, et al. Effects of purified green and black tea polyphenols on cyclooxygenase- and lipoxygenase-dependent metabolism of arachidonic acid in human colon mucosa and colon tumor tissues. Biochem Pharmacol 2001;62:1175-83
Hoshiyama Y, et al. A prospective study of stomach cancer death in relation to green tea consumption in Japan. Br J Cancer 2002;87:309-13
Huang MT, et al. Effects of tea, decaffeinated tea, and caffeine on UVB light-induced complete carcinogenesis in SKH-1 mice: demonstration of caffeine as a biologically important constituent of tea. Cancer Res 1997;57:2623-9
Hsu SD, et al. Chemoprevention of oral cancer by green tea. Gen Dent 2002;50:140-6
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Jian L, Xie LP, Lee AH, Binns, CW Protective Effect Of Green Tea Against Prostate Cancer: A Case Control Study In Southeast China Int J Cancer:108. 130-135 (2004)
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Katiyar SK et al. Polyphenolic antioxidant epigallocatechin gallate from green tea reduces UVB-induced inflammatory responses and infiltration of leukocytes in human skin. Photochem Photobiol 1999; 69:148-53
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Komori A, Yasunami J, et al. Anticarcinogenic activity of green tea polyphenols. Jpn J Clin Oncol 1993; 23:186-90
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Larsson, Susanna, Wolk Alicja, Karolinksa Institute. A relationship between the amounts of tea a middle-age woman drinks and her risk for ovarian cancer. Archives of Internal Medicine. Dec. 12 issue.
Lean ME et al. Dietary flavonols protect diabetic human lymphocytes against oxidative damage to DNA. Diabetes 1999; 48:176-81
Lee IP et al. Chemopreventive effects of green tea against cigarette smoke-induced mutations in humans. J Cell Biochem 1997; Suppl 27:68-75
Lee YK, et al. VEGF Receptor Phosphorylation Status and Apoptosis is Modulated by a Green Tea Component, Epigallocatechin-3-gallate (EGCG) in B cell Chronic Lymphocytic Leukemia. Blood 2004;104(3):788-94
Liao S, Hipakka RA. Selective inhibition of steroid 5-alpha-reductase isozymes by tea epicatechin-3-gallate and epigallocatechin-3-gallate. Biochem Biophys Res Commun 1995;214:833-38
Liao S, Umekita Y et al. Growth inhibition and regression of human prostate and breast tumors in athymic mice by tea epigallocatechin gallate. Cancer Lett 1995; 96:239-43
Lin YL, Cheng CY, et al. Hypolipidemic effect of green tea leaves through induction of antioxidant and phase II enzymes including superoxide dismutase, catalase, and glutathione S-transferase in rats. J Agricult Food Chem 1998;46:1893-99
Lu LH, Lee SS, Huang HC. Epigallocatechin suppression of proliferation of vascular smooth muscle cells: correlation with c-jun and JNK. Brit J Pharmacol 1998;124:1227-37
McCarty MF. Polyphenol-mediated inhibition of AP-1 transactivating activity may slow cancer growth by impeding angiogenesis and tumor invasiveness. Med Hypoth 1998; 50:511-14
Morre D, Morre DJ. Findings on epigallocatechin gallate and tNOX inhibition presented at the 38th annual meeting of the American Society for Cell Biology; summary available at http//www.uns.purdue.edu
Naasani I et al. Telomerase inhibition, telomere shortening, and senescence of cancer cells by tea catechins. Biochem Biophys Res Commun 1998; 249:391-96
Nagata C et al. Associations of coffee, green tea, and caffeine intakes with serum concentrations of estradiol and sex hormone-binding globulin in premenopausal Japanese women. Nutr Cancer 1998; 30:21-24
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Oguri A et al. Inhibitory effects of antioxidants on formation of heterocyclic amines. Mutat Res 1998; 402:237-45
Otsuka T, Ogo T, et al. Growth inhibition of leukemic cells by epigallocatechin gallate, the main constituent of green tea. Life Sciences 1998; 63:1397-1403
Parshad R, Sanford RR, et al. Protective action of plant polyphenols on radiation-induced chromatid breaks in cultured human cells. Anticancer Res 1998;18:3263-66
Pashka AG et al. Induction of apoptosis in prostate cancer cell lines by the green tea component, epigallocatechin gallate. Cancer Lett 1998;130:1-7
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Proniuk S, et al. Preformulation study of epigallocatechin gallate, a promising antioxidant for topical skin cancer prevention. J Pharm Sci 2002;91:111-6
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Sai I, Kai S et al. Protective effects of green tea on hepatotoxicity, oxidative DNA damage and cell proliferation in the rat liver, induced by repeated oral administration of 2-nitropropane. Food Chem Toxicol 1998; 6:1043
Sartippour MR, et al. Green tea inhibits vascular endothelial growth factor (VEGF) induction in human breast cancer cells. J Nutr 2002;132:2307-11.
Sazuka M, Imazawa H, et al. Inhibition of collagenases from mouse lung carcinoma cells by green tea catechins and black tea theaflavins. Biosci Biotechnol Biochem 1997; 61:1504-06
Smith DM, et al. Green tea polyphenol epigallocatechin inhibits DNA replication and consequently induces leukemia cell apoptosis. Int J Mol Med 2001;7:645-52
Suganuma M, Okabe S, et al. Synergistic effects of epigallocatechin gallate with epicatechin, sunlilndac, or tamoxifen on cancer-preventive activity in the human lung cancer cell line PC-9. Cancer Res 1999;59:44-7
Sugiyama T, Sadzuka Y. Combination of theanine with doxorubicin inhibits hepatic metastasis of M5076 ovarian sarcoma. Clin Cancer Res 1999; 5:413-16
Sugiyama T, Sadzuka Y. Enhancing effects of green tea components on the antitumor activity of adriamycin against M5076 ovarian sarcoma. Cancer Lett 1998; 133:19-26
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Yang CS, et al. Blood and urine levels of tea catechins after ingestion of different amounts of green tea by human volunteers. Cancer Epidemiol Biomarkers Prev 1998;7:351-4.
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Yang CS, et al. Human salivary tea catechin levels and catechin esterase activities: implications in human cancer prevention studies. Cancer Epidemiol Biomarkers Prev 1999;8:83-9
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