MMP9 and endometriosis: MMP9 encodes for a metalloproteinase that has a purported role in the progression of invasion in endometriosis as well as angiogenesis and fibrosis (Ke et al., 2021), has involvement in a variety of inflammatory autoimmune diseases, and has been suggested to be a therapeutic target for autoimmune conditions (Ram et al., 2006; Liu et al., 2019).