MMP9 and neoplasm: Studies have shown that the high expression of COX‐2 is closely related to the occurrence of breast cancer because tumor cells can maintain high levels of ROS by overexpressing COX‐2 (Hou et al., 2011), leading to the promotion of tumor progression by increasing MMP2 (Sivula et al., 2005) and MMP9 expression (Liou & Storz, 2010; Mohammad et al., 2012) and excessive angiogenesis by increasing VEGFA protein synthesis and secretion (Davies et al., 2003; von Rahden et al., 2005).