MMP7 and colorectal cancer: Next, we selected MMP-7 as a target gene from these candidate MMPs because we found that only the MMP-7 mRNA expression was significantly higher on plastic than that on a gel (Supplementary Figure S1a), and overexpression of MMP-7 protein is a well-known prognostic marker in colorectal cancer.25 We also found that the protein expression of MMP-7 on a stiff substrate was significantly higher than that on a soft substrate (Figure 1c and Supplementary Figure S1b).