Arginase-1 mRNA expression correlates with myeloid-derived suppressor cell levels in peripheral blood of NSCLC patients

Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of immature and progenitor myeloid cells with immunosuppressive activity that are increased in cancer patients. Until now, the characterization of MDSC in humans was very challenging. The aim of this study was to determine the characterization and optimal assessment of MDSC and to investigate their presence and function in blood of advanced-stage NSCLC patients. We determined MDSC and lymphocyte populations in peripheral blood mononuclear cells (PBMC) samples of 185 treatment-naive NSCLC patients and 20 healthy controls (HC). NSCLC patients had an increased population of PMN-MDSC compared to HC (p<0.0001). Frequencies of CD4(+) and CD8(+) T-cells were significantly decreased in NSCLC patients (p