TGFB1 and breast cancer: In addition, other studies indicate that MSCs induce a protective effect on breast cancer cells by Treg cell promotion [21], thereby inhibiting the function of immune cells such as NK cells and lymphocytes, among others, through the expression of immunosuppressive factors including IL-4, IL-10, and TGF-β [22], whose presence could be a determinant in tumor pathogenesis and generate an immunosuppressive environment [23,24].