Moreover, the expression of immune checkpoints (programmed cell death protein-1 [PD-1] and PD-1 cognate ligand [PD-L1]), which are associated with HCC tumor size, blood vessel invasion, and BCLC staging, can be downregulated by cryoablation but upregulated at recurrence (65). This evidence concerns the gene PDCD1 and hepatocellular carcinoma.