Figure 2.
Immune checkpoints of immunosuppressive actions associated with breast cancer. Immune checkpoints of inhibitory pathways are fundamental in the immune system to maintain self-tolerance and modulate immune responses. In breast cancer, some of these immune checkpoints and immunosuppressive factors have been associated with subtype specificity through their expressions on breast cancer cells. The different immune cells and their ligand-receptor interactions and secreted stimulatory growth factors, chemokines and cytokines are shown. The expression of these immune markers in the TME in breast cancer may or not be subtype-specific but are important in circumventing immune recognition or to immobilize effector T cells. Thus, the expression of these ligands and receptors may be associated with breast cancer stage and clinical outcome. (AKT. serine/threonine kinase or protein kinase B; ARG1. Arginase 1; Bcl-xL. B-cell lymphoma-xtra large; CAFs. Cancer-associated fibroblasts; CTLA4. cytotoxic T-lymphocyte-associated protein 4; ER− Estrogen Receptor Negative; GM-CSF. Granulocyte-Macrophage Colony-Stimulating Factor; HER2+. Human Epidermal Growth Factor Receptor 2; IDO. Indoleamine-2,3-dioxygenase; IFN-γ. interferon gamma; IFN-γR. interferon gamma receptor; IL. Interleukin; JAK. Janus kinase; iNOS. Inducible nitric oxide synthase; MDSC. Myeloid-derived suppressor cells; MHC. major histocompatibility complex; MMP. Matrix Metalloproteinases; mTOR. Mammalian target of rapamycin; MUC. Mucins; NK. natural killer; NF-κB. nuclear factor-κB; NLR. Neutrophil-lymphocyte ratio; NO. Nitric Oxide; PI3K. PI3K.phosphoinositide 3-kinase; PD-1. programmed death-1; PD-L1. Programmed death-ligand1; PGE2. Prostaglandin E2; PR−. Progesterone Receptor Negative; ROS. Reactive Oxygen Species; SHP. Src homology protein-tyrosine phosphatase; Siglec 9. Sialic acid-binding lectins 9; STAT. Signal transducer and activator of transcription; TAMs. Tumor-associated macrophages; TANs. Tumor-associated neutrophils; TGF-β. Transforming Growth Factor-beta; TIL. Tumor-Infiltrating Lymphocytes; TNBC. Triple Negative Breast Cancer; Treg. regulatory T cell; TCR. T cell receptor; VEGF. Vascular endothelial growth factor).