Activity of MMP-2 and MMP-9 in sera of breast cancer patients

Gelatinase A (MMP-2) and gelatinase B (MMP-9) are proteolytic enzymes involved in the process of tumor invasion, and they are considered as possible tumor markers in breast cancer patients. In this study, we examined serum activity of proMMP-2 and proMMP-9 in relation to TNM stage, tumor size, lymph node involvement, grade of differentiation of tumors, as well as steroid and Her2/neu receptor status in breast cancer patients. The activity of gelatinase in the sera of 52 patients was analyzed by SDS-PAGE zymography. The activity of proMMP-2 and proMMP-9 significantly increased with each advancing clinical stage of disease (p=0.02-0.0009) and compared to controls (p=0.015 to p<0.01). We found a positive correlation between the activity of proMMP-2 and proMMP-9 and tumor size (p=0.007; p=0.05). Patients with lymph node-positive cancer have higher proMMP-2 and proMMP-9 activity than those with node-negative cancer. ProMMP-2 and proMMP-9 activity is not associated with the expression of Her2/neu receptors, but patients with Her2/neu overexpression (3+) showed increased proMMP-2 activity. Steroid receptor score is not associated with enhanced gelatinase activity. The relationship between the increase in proMMP-2 and proMMP-9 activity in serum and tumor size and lymph node status suggests the usefulness of these enzymes as staging markers of breast cancer patients.