PCSK9 and malignant colon neoplasm: To further explore the underlying molecular mechanisms of PCSK9 action on colon cancer progression, we performed the 4D-label-free quantitative proteomic analysis using the criteria of p ≤ 0.05 and the fold-change cutoff of quantitative protein rations more than 1.5 or less than 1/1.5 were considered statistically significant (Fig. 6a-d).