Identification of CD4+CD25+CD127- regulatory T cells and CD14+HLA-DR-/low myeloid-derived suppressor cells and their roles in the prognosis of breast cancer

The aim of the present study was to identify cluster of differentiation 4(+) (CD4(+))CD25(+)CD127(-) regulatory T cells (Tregs) and CD14(+) human leukocyte antigen-antigen D-related (HLA(-)DR(-))/low myeloid-derived suppressor cells (MDSCs) in patients with breast cancer of varying stages, and investigate their roles and the potential interactions in the prognosis of breast cancer. A total of 40 patients with breast cancer were included in the study. A total of 30 healthy individuals served as the healthy control. Flow cytometry was performed for the identification of biomarkers. Natural Tregs were characterized by the expression of CD4(+)CD25(+)CD127(-). The MDSC frequency was expressed as the percentage of CD33(+)CD11b(+)HLA(-)DR(-)lineage markers (Lin)(-). The absolute number of Tregs was higher in breast cancer patients compared to the healthy control. The absolute number of Tregs in the patients with stage III or IV breast cancer was higher than those of the stage I or II, respectively. The percentage showed a gradual increase in the patients with breast cancer compared with the normal control. No direct correlation was established between the number or percentage of Tregs and the patient survival. There was a higher percentage of circulating MDSCs in breast cancer patients compared with the normal individuals. A close correlation was established between clinical cancer stage and percentage and total number of circulating MDSCs. To be exact, a significant increase of MDSC percentage and total number was observed in patients with stage III-IV breast cancer compared with the other cancer patients (stage I-II) and the normal individuals. No statistical difference was observed in the 3- and 5-year survival rates in the breast cancer patients with enhanced expression of Tregs, compared with the normal individuals. In conclusion, enhanced expression of CD4(+)CD25(+)CD127(-) Tregs cells and CD33(+)CD11(+)HLA(-)DR(-)LIN(-) MDSCs were identified from patients with breast cancer. Patients with advanced stage breast cancer showed upregulation of such cells. However, these 2 types of cells showed no correlation with the prognosis of breast cancer.