CXCL12 and neoplasm: Analogous to macrophage plasticity, TANs exhibit environment-dependent phenotypic differentiation: anti-tumor N1-TANs are characterized by high expression of interferon-γ-inducible protein 10/TNF-α and production of reactive oxygen species, whereas pro-tumor N2-TANs upregulate CD206 and CXCL12, secrete higher levels of IL-10, and drive immunosuppression by inhibiting T cell activation and upregulating immune checkpoint molecules 142.