Prognostic value of tumor-infiltrating Foxp3+ regulatory T cells in patients with breast cancer: a meta-analysis

Purpose: The prognostic value of tumor-infiltrating Foxp3+ regulatory T cells (Tregs) in breast cancer remains controversial. Therefore, we performed this meta-analysis to determine the impact of Foxp3+ Tregs infiltration on survival outcomes. Methods: Relevant literature was retrieved from Pubmed, Web of science and Cocohrane until May 30, 2016. Meta-analysis was performed using hazard ratios (HRs), odds ratio (OR) and 95 % confidence intervals (CI) as effect measures. Results: Fourteen studies (10,259 patients) were included. Meta-analysis showed that high Foxp3+ Tregs infiltration was correlated with high histological grade (OR= 2.96, 95%CI [2.03-4.31]), estrogen receptor (ER) negativity (OR= 0.38, 95%CI [0.23-0.60]), human epidermal growth factor receptor type 2 (HER2) positivity (OR=2.43, 95%CI [1.69-3.51]). The detection of FOXP3+ Tregs was significantly associated with recurrence-free survival (RFS) of patients (HR = 1.58, 95 % CI [1.03-2.44]). Conclusion: Our meta-analysis suggests that high Foxp3+ Tregs infiltration is associated with poor RFS in breast cancer patients and predicts histological grade, estrogen receptor and HER-2 status.