MMP9 and colorectal cancer: The data of some key molecules associated with the development of CAC were collected from the TCGA database, which showed that mRNA levels of IL-17A, IL-6, and MMP9 were significantly enhanced in CRC samples than in normal colon tissues (Figure 5E), indicating that the increased expression of inflammatory cytokines and MMP9 were involved in the development and progression of colorectal cancer.