Intriguingly, the matrix metalloproteinases (e.g. MMP2, 9, and 14) capable of degrading collagens and proteoglycans were also found to be upregulated in omental metastases (Figure 1A, and Supplementary file 1a), consistent with the idea that ECM degradation and remodeling are essential steps for cancer cell invasion (Shield et al., 2007). Here, MMP2 is linked to cancer.