Wnt-7a is upregulated by norethisterone in human endometrial epithelial cells: a possible mechanism by which progestogens reduce the risk of estrogen-induced endometrial neoplasia.

Progestogens are added to oestrogen in hormone replacement therapy regimens to reduce the risk of endometrial cancer. We have performed in vitro studies analysing gene expression of isolated normal endometrial epithelia cells (NEE) treated with estradiol and the progestogen norethisterone acetate (NETA). We report here for the first time upregulation of the Wnt-7a gene by NETA in estrogen treated NEE. Wnt genes are a large family of developmental genes associated with cellular responses such as oncogenesis. We therefore suggest that upregulation of Wnt-7a may be associated with the antineoplastic effects of progestogens on the endometrium.