MMP-9 is found to play a crucial role in gastric cancer, breast cancer, colorectal cancer, non-small-cell lung cancer, ovarian cancer, and many other cancers (Roy et al., 2009; Shao et al., 2011; Hu et al., 2012; Li et al., 2013; Liang and Chang, 2018). Here, MMP9 is linked to cancer.