In this research, we demonstrated that knock-down of TUSC8 facilitated EMT process through up-regulating the expression of mesenchymal related markers (ZEB1, Twist, SNAI1 and Vimentin), while down-regulating the expression of epithelial related marker (E-cadherin) in breast cancer cell and mice models, thus contributing to the metastasis of breast cancer. The gene discussed is TWIST1; the disease is breast cancer.