EW-7197 is a novel ALK-5 kinase inhibitor as well as TGF-β Type I Receptor Kinase Inhibitor. Study has shown that it can potently inhibit the breast to lung metastasis. Mice study has demonstrated that EW-7197 inhibited Smad/TGFβ signaling, cell migration, invasion, and lung metastasis in MMTV/c-Neu mice and 4T1 orthotopic-grafted mice. EW-7197 also inhibited the epithelial-to-mesenchymal transition (EMT) in both TGFβ-treated breast cancer cells and 4T1 orthotopic-grafted mice. Furthermore, EW-7197 enhanced cytotoxic T lymphocyte activity in 4T1 orthotopic-grafted mice and increased the survival time of 4T1-Luc and 4T1 breast tumor-bearing mice. It can also inhibit hepatic, renal, and pulmonary fibrosis by blocking TGF-β/Smad and ROS signaling. Therefore, it is a potential antitumor reagent.