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). The gene discussed is MMP9; the disease is hepatocellular carcinoma.