From the Kaplan–Meier Plotter website, we obtained the survival curves of CDK1 and CDK4, and the results showed that HCC patients with high expression of CDK1 and CDK4 had shorter OS (Fig. 7A, B), relapse-free survival (Fig. 7C, D), progression-free survival (Fig. 7E, F) and disease-free survival (Fig. 7G, H) than those with low expression, and these results were statistically significant. This evidence concerns the gene CDK4 and hepatocellular carcinoma.