Phase II, Randomized,Double-blind, Placebo-controlled, Study of the Efficacy of Green Tea Extract on Biomarkers of Breast Cancer Risk in High Risk Women With Differing Catechol-O-methyl Transferase (COMT) Genotypes

Trial Information

Phase II, Randomized,Double-blind, Placebo-controlled, Study of the Efficacy of Green Tea Extract on Biomarkers of Breast Cancer Risk in High Risk Women With Differing Catechol-O-methyl Transferase (COMT) Genotypes

OBJECTIVES:

1. Primary:

1.1 To determine the effects of green tea extract consumption (containing 800 mg EGCG
per day) for 12 months on the following recognized biomarkers of breast cancer risk:

1. Mammographic density

2. Circulating concentrations of insulin-like growth factor 1 (IGF-1) and IGF binding
protein 3 (IGFBP-3)

3. Circulating concentrations of reproductive hormones (estrone, estradiol,
androstenedione) and sex hormone binding globulin (SHBG)

1.2 To determine the effects of COMT genotype on the green tea extract effects
described above.

2. Secondary:

2.1 To determine the effects of green tea extract consumption (containing 800 mg EGCG per
day) for 12 months on the following hypothesized biomarkers of breast cancer risk:

1. Urinary estrogen metabolites (estrone, estradiol, and their 2-hydroxy, 4-hydroxy,
2-methoxy, and 4-methoxy metabolites, estriol, and 16- hydroxyestrone)

2. Circulating concentrations of F-2 isoprostanes, a recognized biomarker of systemic
oxidative stress

2.2 To determine the effects of COMT genotype on the green tea extract effects described
above.

2.3 To determine the effects of COMT genotype on catechin metabolism and excretion, as
measured by circulating and urinary concentrations.