ACTA1 and cancer: We also observed increased expression of mesenchymal markers such as α-SMA, β-catenin, and vimentin in Treg-co-cultured B16-BL6 derived tumor tissues (Figure 4B,C), in agreement with previous reports demonstrating that increased α-SMA expression in cancer cells leads to invasion and metastasis of many epithelial cancers [42,43].