Final answer:
Myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment primarily function to inhibit the immune response, including suppression of T cell proliferation and reduction of NK cell activity.
Step-by-step explanation:
The function of myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment (TME) is to inhibit the immune response. MDSCs suppress various aspects of the immune response against tumors, including the inhibition of T cell proliferation and the reduction of NK cell activity. MDSCs exert their suppressive effects through several mechanisms, such as the production of immunosuppressive cytokines, and the induction of regulatory T cells (Tregs), which are known for their capacity to suppress the activity of other immune cells.