Inhibitory effects of nitrative stress on the sulfation of 17β-estradiol and 4-methoxyestradiol by human MCF 10A mammary epithelial cells.

Prolonged exposure to high level of estrogen is a known risk factor for breast carcinogenesis. It has been suggested recently that nitrative stress may be an etiologic factor for breast carcinogenesis. Since sulfation plays a major role in the homeostasis of estrogens and their metabolites, we attempted in the present study to find out whether nitrative stress may affect the homeostasis of estrogens through sulfation.