Effects of a green tea extract, Polyphenon E, on systemic biomarkers of growth factor signalling in women with hormone receptor-negative breast cancer

BackgroundObservational and experimental data support a potential breast cancer chemopreventive effect of green tea. MethodsWe conducted an ancillary study using archived blood/urine from a phase IB randomised, placebo-controlled dose escalation trial of an oral green tea extract, Polyphenon E (Poly E), in breast cancer patients. Using an adaptive trial design, women with stage I-III breast cancer who completed adjuvant treatment were randomised to Poly E 400mg (n=16), 600mg (n=11) and 800mg (n=3) twice daily or matching placebo (n=10) for 6months. Blood and urine collection occurred at baseline, and at 2, 4 and 6months. Biological endpoints included growth factor [serum hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF)], lipid (serum cholesterol, triglycerides), oxidative damage and inflammatory biomarkers. ResultsFrom July 2007-August 2009, 40 women were enrolled and 34 (26 Poly E, eight placebo) were evaluable for biomarker endpoints. At 2months, the Poly E group (all dose levels combined) compared to placebo had a significant decrease in mean serum HGF levels (-12.7% versus +6.3%, P=0.04). This trend persisted at 4 and 6months but was no longer statistically significant. For the Poly E group, serum VEGF decreased by 11.5% at 2months (P=0.02) and 13.9% at 4months (P=0.05) but did not differ compared to placebo. At 2months, there was a trend toward a decrease in serum cholesterol with Poly E (P=0.08). No significant differences were observed for other biomarkers. ConclusionsOur findings suggest potential mechanistic actions of tea polyphenols in growth factor signalling, angiogenesis and lipid metabolism.