Myeloid-derived suppressor cells in cancer.

Numerous recent studies have shown that myeloid-derived suppressor cells (MDSCs), a strongly heterogeneous population of immunosuppressive cells, are dysregulated in the presence of many cancers. MDSCs present different phenotypes and play prominent roles in the tumor microenvironment. To date, gene therapies targeting MDSCs are the most innovative and flexible methods to specifically modify the tumor microenvironment. Here, we summarize current studies related to the phenotypes, functions, and mechanisms of MDSCs and explore the therapeutic landscape of chemokines that affect the balance between subpopulations of MDSCs.