Association of myeloid-derived suppressor cells (MDSCs) in peripheral blood with characteristics in breast cancer patients.

Abstract

e22094 Background: The immune therapy of human cancer is a promising therapeutic approach. Myeloid-derived suppressor cells (MDSCs) have been confirmed as an indispensable component of immune system and associated with tumor induced immune suppression. Thus, MDSCs play an important role in immune therapy. Although a lot of research work has been done, currently there exists limited data about MDSCs status in cancer patients. The aim of this study was to determine whether MDSCs levels in peripheral blood were different in healthy volunteers, benign breast tumor patients and breast cancer patients, and to investigate the relation between MDSCs and several characteristics in breast cancer patients. Methods: Peripheral blood cells (PBC) were collected from 36 normal healthy volunteers, 52 patients with breast cancer and 62 patients with benign breast tumor. Peripheral blood samples of breast cancer patients were obtained before treatment. Circulating MDSCs (identified as Lin-/Lo HLA-DR-CD33+) were measured by flow cytometry. Statistical methods included two sample t tests and one way ANOVA. Results: The percentage of MDSCs was higher in breast cancer than benign breast tumor patients and healthy volunteers (2.017% vs 1.578% vs1.594%; p=0.0002), and the stage III/IV breast cancer patients had more MDSCs accumulation than those in stage I/II (2.92% vs 2.155%; P=0.0806). The levels of MDSCs in peripheral blood showed a significant correlation with HER-2/neu expression in breast cancer patients, but had no correlation with incidence age, ER status, PR status and P53 expression respectively. The percentage of MDSCs was lower in HER-2/neu over expression breast cancer patients than HER-2/neu negative patients (1.715% vs 2.882%, GP=0.0012). Conclusions: MDSCs seemed to have positive correlation with clinical stage and negative correlation with HER-2/neu expression in breast cancer patients . Further research will contribute to the better understanding of the connection between MDSCs and breast cancer, to develop better approaches to breast cancer therapy.