PCSK9 and malignant colon neoplasm: We therefore detected the changes in such protein expressions in colon cancer cells (i.e., knockdown of PCSK9 expression significantly upregulated level of E-cadherin protein), but downregulated expressions of N-cadherin, MMP9, and Snail 1 proteins in HCT116 and HT-29 cells (Fig. 4c and d).