MMP9 and cancer: It is well known that VEGF and MMP9 are critical proteins for cancer cell invasion and metastasis and that the autocrine secretion of these cytokines by cancer cells critically influences cancer cell behaviours such as invasion.25 When SSRP1 was knocked down in HCT116 cells, MMP9 and VEGF were down‐regulated (Figure 3D), and the opposite regulation was seen in SSRP1‐overexpressing cells.