Epidemiologic data support an inverse association between green tea intake and breast cancer risk. Greenselect®Phytosome® (GSP) is a lecithin formulation of a caffeine-free green tea catechin extract. The purpose of the study was to determine the tissue distribution of Epigallocatechin-3-O-gallate (EGCG) and its effect on cell proliferation and circulating biomarkers in breast cancer patients. Twelve early BC patients received GSP 300 mg, equivalent to 44.9 mg of EGCG, daily for 4 weeks prior to surgery. The EGCG levels were measured before (free-) and after (total-) enzymatic hydrolysis by HPLC-MS/MS in plasma, urine, breast cancer tissue and surrounding normal breast tissue. Fasting blood samples were taken at baseline, before the last administration and 2 hours later. Repeated administration of GSP achieved levels of total-EGCG ranging from 17 to 121 ng/mL in plasma. Despite a high between-subject variability, total EGCG was detectable in all tumor tissue samples collected up to 8 ng/g. Median total-EGCG concentration was higher in the tumor as compared to the adjacent normal tissue (3.18 ng/g vs. 0 ng/g, P=0.02). Free-EGCG concentrations ranged from 8 to 65.8 ng/mL in plasma (P between last administration and 2 hours after <0.001). Free-EGCG plasma levels showed a significant positive correlation with the Ki-67 decrease in tumor tissue (P=0.02). No change in any other biomarkers was noted, except for a slight increase in testosterone levels after treatment. Oral GSP increases bioavailability of EGCG, which is detectable in breast tumor tissue and is associated with antiproliferative effects on breast cancer tissue.
- Received November 21, 2016.
- Revision received March 31, 2017.
- Accepted April 7, 2017.
- Copyright ©2017, American Association for Cancer Research.