The pivotal role of CD8+ T cells and NK cells in antitumor immunity is underscored by the fact that expression of CD8A and CD8B mRNA as well as KLRK1 and KLRB1 mRNA (encoding the human homologs of CD314 and NK1.1, respectively) in HCC is associated with patient survival (P < 0.05; Supplemental Table 2). This evidence concerns the gene KLRB1 and hepatocellular carcinoma.