TGFB1 and neoplasm: For instance, Tan et al. showed that Tregs promote invasion and metastasis in mammary cells via activation of receptor activator of nuclear factor-κB ligand (RANKL) signaling [11], while, Shi et al. showed that tumor-infiltrating Tregs promote invasion of hepatocellular carcinoma via epithelial–mesenchymal transition induced by TGF-β1 secretion [68].