Figure 1.

Immune cells in the tumor microenvironment: roles in tumor killing and immune suppression. Immune cells may evolve into antitumor or pro-tumor phenotypes in response to their microenvironment. Here, we review the category of the major innate immune cell lineages (in rows) based on their roles in tumor killing and immune suppression (light blue, left; pale red, right, respectively). Main transcription factors occupy the center of each cell; blue arrows indicate cytokines upstream of each phenotype, whereas yellow arrows indicate downstream cytokines. cDC1, conventional dendritic cells 1; pDC, plasmacytoid dendritic cells; NK, natural killer cells; ILC 2, innate lymphoid cell type 2; TH1/2, CD4⁺ T helper cell types 1 or 2; CD8+ T: CD8+ T cells; Tregs: CD4+ regulatory T cells.