Immunohistochemistry tests were performed in breast cancer sections in order to locate signal from each protein in the tissues, several members from the metalloproteinases system (MMP-1, MMP-3, MMP-9, and inhibitor TIMP-1) and also from the fibrinolytic system (uPA, uPAR, and PAI-1) were specifically screened, and then a comparison of their semiquantitative expression was obtained as a numeric value of signal intensity (IOD), in the two groups of cancer patients: N0 with no metastasis and N1 with metastatic cancer in close ganglia nodes. The gene discussed is MMP9; the disease is metastatic malignant neoplasm.