The Role of Myeloid Derived Suppressor Cells in Urothelial Carcinoma Immunotherapy

Myeloid derived suppressor cells (MDSC) are immune cells that dampen immune responses. In patients with cancer, MDSC are associated with adverse oncologic outcomes and therapeutic resistance. Pre-clinical evidence suggests that MDSC suppress anti-tumor immune responses. In this report, the biologic functions of MDSC are defined and evidence linking MDSC with the response to cancer immunotherapies in solid tumors are reviewed. Associations of MDSC in clinical bladder cancer cohorts are outlined in addition to evaluation of the suggested roles of MDSC in pre-clinical bladder cancer models. Human clinical trials that investigate possible MDSC modulators are highlighted, and therapeutic strategies to leverage MDSC biology in bladder cancer immunotherapy are outlined.