The risk score of each HCC patient was calculated as follows: Risk score = 0.4635* NRAV expression level +0.8199* MKLN1-AS expression level +0.6452* AL031985.3 expression level + 0.3553* ELFN1-AS1 expression level +0.7350* AL928654.1 expression level. The gene discussed is ELFN1; the disease is hepatocellular carcinoma.