BACKGROUND: T cells essential for maintaining immune balance and preventing autoimmunity by expressing CD25 and CTLA-4. Tregs, which are defined by the expression of the transcription factor FOXP3 in mice, restrain excessive immune activation through mechanisms such as IL-10 expression, TGF-β expression, metabolic regulation, acting as an IL-2 cytokine sink, and cell-to-cell interaction through co-inhibitory receptors. Although they are indispensable for immune tolerance, Tregs can be co-opted by tumors, where their suppressive activity promotes immune escape. High Treg infiltration within the tumor microenvironment has been linked to variable prognosis depending on the tumor type, highlighting Tregs' contradictory roles as both guardians of tolerance and enablers of tumor progression. DESIGN: In this review, we summarize Treg biology, Tregs' contribution to cancer immunity, and emerging therapeutic strategies designed to modulate or deplete Tregs. We conducted a targeted literature review using PubMed/MEDLINE, Web of Science, ClinicalTrials.gov, and ASCO/ESMO meeting libraries, complemented by manual reference screening. We also discuss the limitations of existing therapeutic approaches and outline future directions. RESULTS: cells, which may help predict therapeutic response. CONCLUSION(S): A deeper understanding of Treg regulation is needed to unlock their therapeutic potential without compromising immune equilibrium.
Mirallas et al. (Wed,) studied this question.