TGFB1 and neoplasm: Briefly, TGF-β1 acts as a tumor suppressor mainly through its ability to inhibit cell proliferation both by inducing the expression of cyclin-dependent kinase inhibitors such as p21Cip1 and p15lnk4b, and/or by reducing the expression of proliferative drivers such as c-Myc and cyclin-D (44–46).