CD4 and neoplasm: Figure 6F shows that PJVK was positively correlated with CD4+ T cells (Cor = 0.122, p < 0.05), whereas it was negatively correlated with other immune cells, except B cells. Natural killer cell (NK) is an important immune cell and closely related with anti-tumor response. Unlike T and B cells, NK cells are a class of lymphocytes that can non-specifically kill tumor cells without pre-sensitization. We analyzed the infiltration of NK cells in LUAD by using ssGSEA (Figure 6G).