The risk score was calculated as follows: score = -0.0354 × expression level of ADH1A—0.0035 × expression level of ADH1B − 0.0100 × expression level of CYP3A4 + 0.113 × expression level of FCGBP + 0.119 × expression level of PABPC1 + 0.126 × expression level of NDRG1. Figure 5B shows that the expression of these 6 genes was significantly different in HCC tissues and adjacent normal tissues. Here, CYP3A4 is linked to hepatocellular carcinoma.