Myeloid-derived suppressor cells

Abstract

Myeloid cells evolutionary developed as a major mechanism to protect the host. They evolved as a critical barrier against infections and are important contributors to tissue remodeling. However, in cancer, myeloid cells are largely converted to serve a new master – tumor cells. This process is epitomized by myeloid-derived suppressor cells (MDSC). These cells are closely related to neutrophils and monocytes. MDSC are not present at steady state in healthy individuals and appear in cancer and pathological conditions associated with chronic inflammation or stress. These cells have emerged as an important contributor to tumor progression. In recent years, ample evidence supports a key role of MDSC in immune suppression in cancer, as well as their prominent role in tumor angiogenesis, drug resistance, and promotion of tumor metastases. MDSC have a fascinating biology and are implicated in limiting the effects of cancer immunotherapy. Therefore, targeting these cells may represent an attractive therapeutic opportunity.