DACT1 inhibited the tumorigenicity of breast cancer in vivo. (A) Tumors derived from vector- (black arrows), and DACT1-expressing (red arrows) MB231 cells in nude mice. (B) Tumor growth curve of DACT1-expressing cells in nude mice compared with control tumors. **P < 0.01. (C) Representative photographs of hematoxylin and eosin (H&E) staining and immunohistochemistry (IHC) analysis of DACT1 and Ki-67 antigen in tumors of nude mice. Magnification, 400×.