TGFB1 and invasive breast carcinoma: Importantly, whereas Foxp3 upregulates TGF-β expression in Tregs by repressing its negative regulator [3], TGF-β also plays a central role in epithelial–mesenchymal transition (EMT) [53], and it is possible that a positive feedback loop between Foxp3 and TGF-β could facilitate EMT in BRCA.