From numerical amplification to functional metamorphosis: the MDSC-driven therapeutic resistance in tumor

Myeloid-derived suppressor cell (MDSC) is a population with immunosuppressive characteristics in the tumor microenvironment, which are linked to poor prognosis and therapeutic resistance across cancers. In this review, a novel concept of MDSC and a quantity-quality pattern are proposed to illustrate the spatiotemporal dynamics of MDSC fate. By reviewing current researches through this framework, a group of pro-tumor signals is identified to have critical roles in the whole life cycle of MDSC evolution, including IMC proliferation, differentiation education, suppressive functioning of MDSC, and targeting strategy.