In our previous study, we reported that syngeneic implantation of recipient mice with PCSK9KO mouse melanoma, breast, and colon cancer cells led to substantially suppressed tumor growth compared with PCSK9 vector-control (VC) tumors in mice, which was independent of host LDLR and cholesterol levels.34 Similarly, Gu and colleagues also suggested a negative correlation between PCSK9 expression and survival probability in melanoma patients. This evidence concerns the gene PCSK9 and malignant colon neoplasm.