Objective To observe the expression of CD_ 105 in breast cancer, and explore the correlation between CD_ 105 and growth, invasion and metabasis of breast cancer. Methods 50 cases of breast infiltrating duct cancer, 20 cases of breast duct cancer and 20 cases of breast benign hyperplasia were enrolled in this study. The microvascular density(MVD) was marked with CD_ 105 and F-8RAg using immunohistochemical S-P method. Results The expression level of CD_ 105 in breast infiltrating duct cancer was significantly higher than that in breast duct cancer and benign hyperplasisa(P