Estrogen receptor β and matrix metalloproteinase 1 are coexpressed in uterine endometrium and endometriotic lesions of patients with endometriosis

We have shown that MMP-1 and ERβ are coexpressed and up-regulated in endometriotic lesions, whereas local ERα expression is down-regulated. The altered ERβ/ERα ratio in endometriotic glands suggests that estrogenic effects on MMP-1 are primarily mediated via ERβ, and the local control of MMP-1 in eutopic endometrium is not different from that observed in healthy cycling women.