For instance, small molecule inhibitors that target the kinase activity of TGF-βRI/ALK5 have been evaluated in preclinical mouse models of cancer (SD-208, SX-007, LY2109761) or are already being tested in clinical studies in cancer patients [(LY573636, LY2157299), ([256] and references therein)]. Here, TGFBR1 is linked to cancer.