The clinical and prognostic significance of CD14⁺HLA-DR^−/low myeloid-derived suppressor cells in hepatocellular carcinoma patients receiving radiotherapy

Myeloid-derived suppressor cells (MDSCs) are key player in mediating systemic immunosuppression, and their accumulation and expansion in the periphery and tumor have been iteratively observed in patients with various types of cancer. It has been reported that CD14⁺HLA-DR^−/low MDSCs are increased in hepatocellular carcinoma (HCC) patients; however, the clinical significance of MDSC alteration in HCC patients after treatment is poorly studied. In this study, we examined the frequency of MDSCs in 92 HCC patients, 14 chronic liver disease patients without HCC, and 22 healthy controls by flow cytometric analysis. The associations between the clinical features and the frequency of MDSCs were analyzed. In particular, we further examined the prognostic impact of MDSCs on the overall survival of HCC patients receiving radiation therapy. The frequency of MDSCs in HCC patients was significantly increased and correlated with tumor stage, size, burden, and Child-Pugh classification but not with biochemical parameters of liver function. In HCC patients who received radiation therapy, the frequency of MDSCs after treatment significantly decreased and was inversely correlated with overall survival time. In multivariate analysis, only post-treatment MDSC ratio and Child-Pugh classification were correlated with the prognosis of HCC patients. Patients with a high frequency of MDSCs after radiotherapy should be closely followed, and the inhibition of MDSCs may improve the prognosis of patients.