Transforming growth factor β1 (TGFβ) induces Treg cells, MC38-EVs significantly promote Treg cell induction in vitro, E2 reduces the level of TGF-β1 in MC38-EVs and impairs Treg induction in MC38-EVs in vitro, which in turn inhibits the growth of mouse colon cancer (81). This evidence concerns the gene TGFB1 and malignant colon neoplasm.