Kaplan-Meier survival analysis showed that the overall survival rate of HCC patients in the high mRNA expression group of CCNB1 (P = 0.00026), CDK4 (P = 0.00016), CDK1 (P = 0.0029), and PLK1 (P = 0.00036) was significantly lower than that of those in the low mRNA expression group (Fig. 7A-D). Here, CDK4 is linked to hepatocellular carcinoma.