Through an immunofluorescence method, we found that PTGS2 inhibition led to a clear downregulation in the expression of the metastasis-related protein MMP9 in both HCT116 and SW480 CRC cell lines (Fig. 2C), supporting the notion that PTGS2 silencing impairs cell migration and invasion in vitro. Here, PTGS2 is linked to colorectal carcinoma.