MMP9 and adenomyosis: Since MMP-3 is a known activator of MMP-9, it’s reasonable to suspect that simvastatin may also act as an inhibitor of MMP-9, thus inhibiting growth of endometrial stromal cells and reducing expression of adenomyosis (Johnson et al. 2011, Piotrowski et al. 2006, Steenport et al. 2009, Wilson et al. 2005).