We first performed lentivirus infection in Huh7 and PLC/PRF/5 cells for the knockdown of PCSK9, whereas performed overexpression of PCSK9 in cell lines Li7 and MHCC-97H with relative low expression of PCSK9 according to their expression in HCC cell lines (Figure S4A and S4B). The gene discussed is PCSK9; the disease is hepatocellular carcinoma.