The knockdown of progesterone receptor isoform B (PR-B) promotes proliferation in immortalized endometrial stromal cells.

The knockdown of PR-B by siRNA resulted in a significant increase in proliferation in an immortalized endometrial stromal cell line. This suggests that PR-B knockdown might be responsible, at least in part, for increased proliferation and resistance to apoptosis as seen in the eutopic and ectopic endometrium of women with endometriosis.