MMP9 and colorectal carcinoma: Other studies have shown that MMP-9 is highly expressed in cancer tissues such as oral cancer (Xie et al., 2020), GC (Dong et al., 2020), CRC (Guo et al., 2020), breast cancer (Nazir et al., 2019), and cervical cancer (Azevedo Martins et al., 2020), and has been used as a potential marker of cancers (Huang, 2018).