Circulating CD3+ CD8+ T lymphocytes as indicators of disease status in patients with early breast cancer

Abstract

AbstractBackground Identifying breast cancer markers with superior sensitivity, cost-effectiveness, and practicality is imperative. Circulating immune cells and plasma cytokines hold promise as potential breast cancer markers. Methods Using flow cytometry, we investigated circulating immune cell profiles in patients with breast cancer and healthy controls. To validate clinical observations, an orthotopic breast cancer model was established. Results Analysis of 19 healthy controls and 27 patients with breast cancer revealed distinct populations, including CD3+CD4+T lymphocytes, cytotoxic T lymphocytes (CTLs; CD3+CD8+), polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs; CD11b+Ly6C−Ly6G+), and monocytic (M)-myeloid-derived suppressive cells (CD11b+Ly6C+Ly6G−). Patients with breast cancer exhibited reduced CD3+CD4+T lymphocyte, CD3+CD8+CTL, and CD33+CD15−M-MDSC levels compared with healthy controls. Diminished CD3+CD8+CTL levels correlated with advanced cancer grade, extensive intraductal components, and positive lymphatic tumor emboli. Treatment effects included decreased T lymphocyte/PMN-MDSC levels, contrasting with elevated circulating CD3+CD8+cell levels posttreatment, subsequently declining upon recurrence. Elevated plasma chemokine (C–C motif) ligand 2 (CCL2) levels distinguished patients with breast cancer from healthy controls. Furthermore, our orthotopic model supported that decreased circulating CD3+CD8+CTL levels in cancer-bearing mice, followed by a postresection increase. Conclusions Circulating CD3+CD8+CTL and plasma CCL2 levels emerged as promising dual-purpose biomarkers and therapeutic targets in breast cancer management.