GZMK and hepatocellular carcinoma: Pairwise comparisons among NK cell subsets revealed 25 highly expressed common genes across the 5 NK cell subsets in the blood and tumor tissues of patients with HCC (Figure 6D), including genes encoding secretory effector proteins (LAIR2, GNLY, IFNG, GZMK, and XCL1), transcriptional regulators (EGR1 and EOMES), membrane proteins (TIGIT, TKT, HLA-DRA, RHOB, HLA-DRB1, ADGRG1, KLRC1, KLRG1, NCR3, FCGR3A, and CXCR4), and other products (Figure 6E).