Increased circulating CD14(+)HLA-DR-/low myeloid-derived suppressor cells are associated with poor prognosis in patients with small-cell lung cancer.

Abstract

High expression of CD14(+)HLA-DR-/low myeloid-derived suppressor cells (MDSCs) is correlated with immunosuppressive activity in various cancers, however, no studies have shown a correlation of these immunosuppressive cells with clinical outcomes in small-cell lung cancer (SCLC) patients. The purpose of the study was to investigate the number, frequency and clinical significance of CD14(+)HLA-DR-/low MDSCs in SCLC patients. The peripheral blood of 42 patients with SCLC and 37 healthy controls was analyzed by using flow cytometry. The relationships between the number and frequency of MDSCs, clinicopathological features and overall survival(OS) were analyzed. The prognostic value of MDSCs was tested by using univariate and multivariate analysis. Our results demonstrated that number and frequency of peripheral CD14(+)HLA-DR-/low MDSCs were significantly increased in SCLC patients than in controls (p< 0.0001 and p< 0.0001, respectively). The frequency of MDSCs correlated with tumor stage (p= 0.02), serum LDH levels (p= 0.001) and with the poorer OS (log-rank test, p= 0.017). Univariate and multivariate analyses suggested that frequency of CD14(+)HLA-DR-/low MDSCs as an independent biomarker for poor prognosis in SCLC patients during follow-up. Our study provides the first evidence that the frequency of CD14(+)HLA-DR-/low MDSCs negatively correlates with clinical outcomes in SCLC patients. The frequency of CD14(+)HLA-DR-/low MDSCs could be considered as a poor prognostic predictor in SCLC and the elimination of MDSCs during medical interventions may improve the prognosis of SCLC patients.