This research identifies a specific cell population known as cycling regulatory T cells (cycTreg) as the primary driver of immune suppression during the transition from ductal carcinoma in situ (DCIS) to invasive breast cancer (IBC). By utilizing single-cell transcriptomics and spatial mapping across human cohorts and rat models, the authors demonstrate that type 2 dendritic cells (cDC2) and IL-33-producing fibroblasts stimulate the expansion of these suppressive cells. Clinical data reveal that cycTreg levels serve as a powerful diagnostic biomarker, predicting a higher risk of recurrence in DCIS and shorter survival in invasive cases. The study identifies OX40 and ST2 as critical therapeutic targets, showing that neutralizing these pathways can reduce cycTreg abundance and reactivate CD8+ cytotoxic T cells. Ultimately, these findings offer a new framework for immunotherapy aimed at preventing breast cancer progression by disrupting the signaling loops that allow tumors to escape immune detection.

References:

• Bui T M, Jimenez E R, Li Z, et al. Identification of cycling regulatory T cell precursors as conductors of immune escape during breast carcinoma progression[J]. Cancer Cell, 2026.