Coffee Consumption and CYP1A2*1F Genotype Modify Age at Breast Cancer Diagnosis and Estrogen Receptor Status.
CYP1A2 plays a key role in the metabolism of both estrogen and coffee. Women with higher coffee intake and the CYP1A2*1F A/A genotype have a ratio of high 2-hydroxyestrone (2-OHE1) to 16alpha-OHE1. 2-OHE1 is a weak estrogen and may even block the estrogen receptor (ER), whereas 16alpha-OHE1 is procarcinogenic. We hypothesized that moderate to high coffee consumption (>/=2 cups per day) combined wi
