In addition, we explored the differential expression of several immune checkpoints in high-risk and low-risk HCC patients and found that Programmed death-1 (PD-1), Programmed cell death-ligand 1(PD-L1), Cytotoxic T-lymphocyte-associated protein 4 (CTLA4), B7 homolog 3 protein (B7-H3), V-Set Immunoregulatory Receptor (VSIR), Lymphocyte activation gene 3 (LAG3) and T-cell immunoreceptor with immunoglobulin and ITIM (TIGIT) were all highly expressed in high-risk patients (Figure 6C). Here, CTLA4 is linked to hepatocellular carcinoma.