Roles Of ECM₁ In The Lymphatic Metastasis Of Breast Carcinoma

[Objective] To investigate the protein and mRNA expression of extracellular matrix protein-1 (ECM1) in human breast carcinoma and the correlation between ECM1 protein and lymphatic microvessel density (LMVD), and to reveal the roles of ECM1 in the lymphatic infiltration and metastasis of human breast carcinoma.[Methods] 1. The protein expression of ECM1 was examined in the cancerous tissues, their normal counterparts and axillary lymph nodes in 41 cases of breast carcinoma by immunohistochemistry. Lymph vessels were labeled by using D2-40 and LMVD was calculated. The correlation between the expression of ECM1 protein and LMVD was analyzed.2. The relative expression level of ECM1 mRNA was detected in the correspongding tissues of the above subjects by real-time fluorescent quantitative polymerase chain reaction.3. The clinicopathological factors were taken into account to analyze the correlation between expression of ECM1 and lymphangiogenesis in breast carcinoma, and the roles of ECM1 in the lymphatic infiltration and metastasis of human breast carcinoma.[Results] 1. LMVD in the carcinoma tissues (12.95±11.10 per 400x field of vision) was higher than that in the corresponding normal breast epithelial tissues (2.24±1.14 per 400x field of vision) and that in the axillary lymph nodes (5.49±3.36 per 400x field of vision) (P<0.01). LMVD in the axillary lymph nodes with lymph node metastases (9.32±9.03 per 400x field of vision) was higher than that without metastases (2.18±1.50 per 400x field of vision) (P<0.01).2. The positive rate of ECM1 protein expression in the breast carcinoma tissues, their normal counterparts and the axillary lymph nodes were 75.6%(31/41), 9.8%(4/41), 29.3%(12/41), respectively. The positive rate of ECM1 expression in the breast carcinoma tissues was higher than that in the corresponding epithelial tissues and axillary lymph nodes (χ2=39.91, P<0.01). The positive rate of ECM1 in positive lymph nodes (12/19, 63.2%) was higher than that in negative lymph nodes (P<0.01).The relative expression of ECM1 mRNA in the breast carcinoma tissues was higher than that in the corresponding epithelial tissues and axillary lymph nodes (P<0.01).3. The protein expression of ECM1 was positively correlated with LMVD in the breast carcinoma tissues (r=0.347, P<0.05).4. The protein expression of ECM1 in the breast carcinoma tissues didn't correlate with premenopause or postmenopause, pathological features, histological classfication, size of primary tumor or status of lymph node metastasis (P>0.05, respectively).[Conclutions] 1. The expression of ECM1 protein and mRNA in the breast carcinoma tissues were both higher than those in the corresponding breast epithelial tissues and axillary lymph nodes.2. The protein expression of ECM1 was positively correlated with LMVD in the breast carcinoma tissues. ECM1 might faciliate lymphangiogenesis, to promote lymphatic infiltration and metastasis of human breast carcinoma.3. Lymphangiogenesis played a key role in the process of breast carcinoma cells disseminating to lymph vessels. The new-born lymph vessels were the main access for breast carcinoma cells to lymphatic metastasis.