To explore the functions of Twist in breast cancer and investigate whether the alteration of Twist has an effect on the expression of MMP-2 and MMP-9, we determined the expression of Twist, MMP-2 and MMP-9 proteins in 200 breast cancer tissue specimens by immunohistochemical (IHC) assay, and studied the correlation between Twist expression and clinicopathological characteristics in the breast cancer tissue samples. Here, MMP9 is linked to breast cancer.