Green tea polyphenols: biology and therapeutic implications in cancer.

Multiple lines of evidence, mostly from population-based studies, suggest that green tea consumption is associated with reduced risk of several human malignancies such as cancer and diabetes. Epigallocatechin-3-gallate (EGCG), a major polyphenol found in green tea, is a widely studied chemopreventive agent with potential anticancer activity. Green tea polyphenols inhibit angiogenesis and metastasis, and induce growth arrest and apoptosis through regulation of multiple signaling pathways. Specifically, EGCG regulates expression of VEGF, matrix metalloproteinases, uPA, IGF-1, EGFR, cell cycle regulatory proteins and inhibits NFk B, PI3-K/Akt, Ras/Raf/MAPK and AP-1 signaling pathways, thereby causing strong cancer chemopreventive effects. This review discusses the molecular mechanisms of green tea polyphenols and their therapeutic implications in cancer.