# Combined elevation of myeloid-derived suppressor cells and Tregs predicts lymph node metastasis in breast cancer

## TL;DR

High levels of certain immune cells in blood predict lymph node spread in breast cancer patients.

## Contribution

Combined detection of MDSCs and Tregs improves prediction of lymph node metastasis in breast cancer.

## Key findings

- MDSCs, PMN-MDSCs, M-MDSCs, and Tregs are elevated in breast cancer patients compared to controls.
- MDSCs and Tregs strongly correlate with lymph node metastasis in breast cancer.
- Combining MDSCs and Tregs improves predictive accuracy for lymph node metastasis.

## Abstract

This study investigates the clinical significance of myeloid-derived suppressor cells (MDSCs), including polymorphonuclear MDSCs (PMN-MDSCs) and monocytic MDSCs (M-MDSCs) subsets, and regulatory T cells (Tregs) in the peripheral blood of breast cancer patients.

Using flow cytometry, we analyzed levels of these immunosuppressive cell populations in 107 breast cancer patients and 33 healthy controls at the Breast Centre of the Fourth Hospital of Hebei Medical University (July-November 2021).

Levels of MDSCs, PMN-MDSCs, M-MDSCs, and Tregs were significantly elevated in breast cancer patients compared to controls (P < 0.05). Furthermore, MDSCs, PMN-MDSCs, and Tregs showed a strong positive correlation with lymph node metastasis (P < 0.001). M-MDSCs were also significantly associated, though to a lesser extent (P = 0.045). Receiver operating characteristic (ROC) curve analysis revealed high diagnostic value for these cells in breast cancer. Notably, Tregs exhibited the highest individual area under the curve (AUC = 0.766) for detecting lymph node metastasis. Critically, the combined assessment of MDSCs and Tregs significantly enhanced predictive accuracy for lymph node metastasis, yielding a combined AUC exceeding that of any single marker.

Elevated levels of MDSCs (and their subsets) and Tregs are closely associated with lymph node metastasis in breast cancer. Their combined detection provides an effective predictive tool for lymph node involvement and holds substantial clinical value.