In some biological settings, E2 is profibrotic; for instance, in dermal fibroblasts, E2 promotes fibrosis by inducing TGF-β1 and TGF-β2 expression,35 and in breast cancer cells, E2 increases syndecan-2 and MMP-9 expression through ERα signaling.36 Here, MMP9 is linked to breast carcinoma.