Expression of MMP1, 2, 9, and 11 in breast cancer and metastatic lymph node tissue

Abstract

Invasiv growth requires degradation of extracellular matrix. A number of Zn 2+ -dependent matrix metalloproteinases (MMPs) are associated with this process. In most cases these enzymes are not produced by the malignant epithelium itself but by adjacent breast stroma, suggesting an important role for cell-cell interactions. Materials and methods: We determined the expression patterns of MMP1, MMP2, MMP9 and MMP11 by immunohistochemistry in tissue arrays, containing 50 paraffin-embedded sets of tissues obtained from the malignant tumor of the breast, and 50 paraffin-embedded sets of tissues from metastatic lymph nodes (purchased from Biomax, Biomax Inc, Rockville, MD). Results: MMP2S protein expression was significantly higher in lymph node tumor tissue when compared to matched breast tumor tissue (10% vs. 2%; p=0.005, Chi Square Test). Furthermore, MMP9S was also significantly up-regulated in lymph node tumor tissue when compared to breast tumor tissue (78.3% vs. 94.8%, p=0.01 Chi Square test) and MMP9E showed a borderline significance in lymph node tumor tissue (92.6% vs. 73.5%, p=0.05). While in the subgroup breast tissue significant correlations were observed between all MMPs except MMP2S this associations were less pronounced in the subgroup lymph node. Conclusions: The increased protein expression of MMP2S, MMP9S and MMP9E in lymph node tissue is in line with other studies which suggested MMP2 and MMP9 expression in primary breast cancer tissue samples was associated with breast cancer progression and invasion [20–23].