High MMP9 gene expression, and low ESR1 gene expression, were closely associated with poor prognosis in HCC patients (log-rank P < 0.001; Figures 6A,D), whereas the expression levels of the other genes had no significant effects on the prognosis of HCC patients (Figures 6B,C,E,F). This evidence concerns the gene ESR1 and hepatocellular carcinoma.