Background & objective: Previous researches of breast cancer mainly focused on its parenchyma and prognosis; however, the relationship between extracellular matrix of breast carcinoma and metastasis as well as prognosis was still unknown. The present study was designed to investigate the expression of matrix metalloproteinase 9 (MMP-9) and laminin- receptor (LM-R) in breast carcinoma and their correlation with tumor metastasis and prognosis.
Methods: The immunohistochemical method was applied to examine the expression of MMP-9 and LM-R in 80 samples of breast carcinoma and 10 breast tissues of hyperplasia. The absorbance(A) values that indicate the expression levels were analyzed by computer image technique. t-test, chi square-test and other related tests were used to analyze their relationship with tumor metastasis and prognosis.
Results: The expression of MMP-9 in breast carcinoma was apparently higher than that in hyperplasia (t=8.87, P< 0.05). LM-R expressed at the basal membrane and the edge of some acini and ducts in hyperplasia tissues, while expressed at cytoplasm and cellular membrane in breast carcinoma tissues. LM-R expression of tumor in 17 cases with LM-R expression in basal membrane was higher than that in those without LM-R expression in basal membrane (t=2.02, P< 0.05). LM-R expression was related to histological grade; the lower the degree of differentiation, the higher the expression level (F=3.27, P< 0.05). The expression of MMP-9 and LM-R related to lymphatic metastasis. The expression levels of MMP-9 and LM-R in the group which had more than 3 involved lymph node were lower than those in the group which had less than involved 3 lymph node and no involved lymph node (t(MMP-9)=3.42, t(LM-R)=4.31, P< 0.05). The expression of MMP-9 and LM-R in original focus had significantly positive relation to metastasis(r(MMP-9)=0.654, r(LM-R)=0.755, P< 0.001). MMP-9 had negative relation to progestogen receptor (PR) (r=-0.363,P< 0.05) and positive relation to LM-R (r=0.503,P< 0.01). The expression levels of MMP-9 and LM-R of the group which survived more than 3 years were lower than that in the group which survived less than 3 years (t(MMP-9)=3.57, t(LM-R)=4.22, P< 0.05). Both of MMP-9 and LM-R were negatively related to the survival of the patients with breast carcinoma (r(MMP-9)=-0.387, r(LM-R)=-0.369, P< 0.05).
Conclusion: MMP-9 and LM-R are useful indexes for predicting the metastasis and prognosis of breast cancer.