Myeloid-derived suppressor cells: origin, phenotype, functions, mechanisms of interaction with immune cells during tumor growth

Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of immature myeloid cells. Their function is to inhibit both adaptive and innate immunity. In chronic inflammation, injuries, malignancies, and other pathological conditions, differentiation of myeloid cells follows the path of formation and accumulation of MDSC. Increased interest in the study of MDCS in oncological diseases is associated with their suppressive effect on the antitumor immune response, which contributes to the progressive growth of the tumor. The review provides a detailed description of the origin of MDSC, their phenotypic heterogeneity, analyzes the main mechanisms of the suppressor function of MDSC and their participation in the suppression of antitumor immunity, provides data on the main therapeutic approaches aimed at overcoming the suppressor function of MDSC.