【Abstract】ObjectiveTo investigate the relationship between the expression of urokinase-type plasminogen activator (uPA) mRNA and breast cancer, lymph node metastasis. MethodsSixty patients with breast tumor were selected randomly and the expression of uPA mRNA was detected with RT-PCR. The patients were divided into benign group (18 cases) and malignant group (42 cases) which included 22 cases with lymph node metastasis and 20 cases without lymph node metastasis. The relationship between uPA mRNA expression and breast cancer, lymph node metastasis was analyzed. ResultsAmong these 18 benign tumors, low expression of uPA mRNA was found in 2 cases and the others were negative. While in 42 cases of malignant tumor, uPA mRNA were positive in 22 cases of lymph node metastasis, 16 of which were high expression, 5 of which were moderate expression, and 1 was low expression. uPA mRNA were positive in 18 of 20 cases of nonmetastatic lymph node, 1 of which was high expression, 5 of which were moderate expression and 12 of which were low expression, the other 2 were negative expression. The expression of uPA mRNA had significant difference between benign and malignant tumors (P＜0.05). The expression in lymph node metastasis was much higher than no lymph node metastasis (P＜0.05). ConclusionThe expression of uPA mRNA in malignant breast cancer is obviously higher than that in benign breast tumor. The expression tensity of uPA is highly relevant to lymph node metastasis in malignant breast cancer, which can provide evidence for clinical staging and therapy.