The myeloid derived suppressor cells: Who are they? Can they be used as a diagnostic tool to investigate metastasis in veterinary medicine?

Abstract

Myeloid-derived suppressor cells (MDSCs) are key players in immunosuppression mechanisms that lead to tumor escape and metastasis formation. Studies on these cells in many cancer types using human patients and murine models, have greatly increased since their discovery in 1980s. MDSCs are now defined as different subpopulations with specific phenotypes in mice and humans with clear immunosuppressive capacities, which are summarized in this review. Current knowledge on these cells have allowed comparative studies and MDSCs have also recently been identified in dogs. As in other species, canine MDSCs have immunosuppressive activities and their number is increased in blood of metastasis-bearing dogs. Circulating MDSCs could therefore represent a new biomarker for cancer progression in both veterinary and human medicine. Further characterization of these cells in other cancer-suffering animal species would also be of great interest.

Keywords: Biomarker; Cancer; Immunosuppressive activities; MDSCs; Phenotype.