Circulating immune biomarkers in peripheral blood correlate with clinical outcomes in advanced breast cancer

Abstract

Identifcation of the diferent elements intervening at the tumor microenvironment seems key to explain clinical evolution in several tumor types. In this study, a set of immune biomarkers (myeloid derived suppressor cells, regulatory T cells, and OX40+ and PD-1 +T lymphocytes counts) in peripheral blood of patients diagnosed with advanced breast cancer were analyzed along of frst line antineoplastic therapy. Subsequently, a comparison between groups with clinical beneft versus progression of disease and with a healthy women cohort was executed. Results refected that patients showed higher basal levels of myeloid derived suppressor cells (35.43, IR= 180.73 vs 17.53, IR= 16.96 cells/μl; p= 0.001) and regulatory T cells (32.05, IR= 29.84 vs 22.61, IR= 13.57 cells/μl; p= 0.001) in comparison with healthy women. Furthermore, an increase in the number of activated T lymphocytes (expressing OX40), a decrease of immune inhibitory cells (MDSCs and Tregs) and inhibited T lymphocytes (expressing PD-1) were observed along the treatment in patients with clinical beneft (p≤ 0.001). The opposite trend was observed in the case of disease progression. These fndings suggest that some critical immune elements can be easily detected and measured in peripheral blood, which open a new opportunity for translational research, as they seem to be correlated with clinical evolution, at least in ABC.