Abstract: Objective :To discuss the relationship and clinical significance in breast cancer and mRNA expression of matrix metalloproteinase-2 (MMP-2) and Fibronectin. Methods :Detect MMP-2 and Fibronectin mRNA expression in 30 cases of primary breast cancer and paired lymphnode metasta-sis by flurence-quantitative RT-PCR and analyze the relativity and clinical siganificance of MMP-2 and Fibronectin mRNA expression with breast cancer metastasis. Results :The MMP-2 and Fibronectin mRNA expression of 30 paired lymphnode metastasis are lower than that of primary breast cancer. The difference is obvious (P<0.05). The MMP-2 and Fibronectin mRNA expression is linear diffusion, but there is no liner relativity between the MMP-2 mRNA expression and Fibronectin mRNA expression (P<0.05). Conclusions :The MMP-2 and Fibronectin mRNA expressions are low gulated in metastatic carcinoma than in primary cancer.