CDKN2A and hepatocellular carcinoma: Four cell cycle-related genes (CDK4, CHEK1, CCNB1, and CDKN2A) were used to establish a risk score to predict the overall survival (OS) of patients with hepatocellular carcinoma (LIHC) in TCGA training set using LASSO Cox regression analysis (Figure 8D and 8E).