(c) flickr & hoher
緑茶の成分，ポリフェノンEが乳がんを予防する機序を示す研究結果が発表された。40名の乳がん患者にポリフェノンEまたはプラセボを6カ月間投与した臨床試験の分析から明らかになった。ポリフェノンEを摂取した患者では，腫瘍細胞の増殖や移動を促進する肝細胞増殖因子と血管内皮増殖因子が抑制されており，これらを介した機序が示唆された。結果を発表した研究者は，この試験は規模が小さいため緑茶の乳がん予防効果を検証したことにはならないが，この物質の抗がん作用機序の解明を推進するだろうと述べた。現在，乳がんの危険性が高い女性での予防を目的とした緑茶抽出物の使用に関し，臨床試験が進行中だ。（吉田素子）
Mechanisms of Action for Green Tea Extract in Breast Cancer Prevention Identified
An oral green tea extract, Polyphenon E, appears to inhibit vascular endothelial growth factor and hepatocyte growth factor, both of which promote tumor cell growth, migration and invasion.
Researchers made this discovery during a secondary analysis of a phase Ib randomized, placebo-controlled study of Polyphenon E in a group of 40 women with hormone receptor-negative breast cancer. Katherine D. Crew, M.D., assistant professor of medicine and epidemiology at Columbia University Medical Center in New York, N.Y., presented the data at the 11th Annual AACR International Conference on Frontiers in Cancer Prevention Research, held here Oct. 16-19, 2012.
“Many preclinical studies have looked at epigallocatechin-3-gallate, or EGCG, which is one of the main components of green tea, and the various possible mechanisms of its action against cancer, but it is very difficult to do those same kinds of studies in humans,” Crew said. “This study was too small to say for sure if green tea will prevent breast cancer, but it may move us forward in terms of understanding antitumor mechanisms.”
In the primary analysis, presented at last year’s Frontiers in Cancer Prevention Research meeting, 40 women were randomly assigned to 400 mg, 600 mg or 800 mg of Polyphenon E or to placebo twice daily for six months. During that time, researchers collected blood and urine samples from participants at baseline and at two, four and six months.
［単語和訳］
Mechanisms of Action：作用機序 Green Tea：緑茶 Extract：抽出物 Breast Cancer：乳がん Prevention：予防
oral：経口投与の Polyphenon E：ポリフェノンE inhibit：～を抑制する vascular endothelial growth factor：血管内皮増殖因子 hepatocyte growth factor：肝細胞増殖因子 tumor cell：腫瘍細胞 growth：増殖 migration：遊走 invasion：浸潤
Researchers：研究者 phase Ib：第Ib相 randomized：無作為化 placebo-controlled study：プラセボ対照試験 hormone receptor-negative：ホルモン受容体陰性の M.D.：医師 assistant professor：助教，講師 epidemiology：疫学
preclinical：前臨床の epigallocatechin-3-gallate：没食子酸エピガロカテキン or ：すなわちcomponents：成分 in terms of：～に関して antitumor：抗腫瘍の
were randomly assigned to：～に無作為に割り当てられた placebo：プラセボ urine：尿 participants：参加者 baseline：ベースライン
