Measurement of MMP-9 Expression Level for Treatment Assessment in Breast Cancer Patients

MMP-9 (matrix metalloproteinase-9) is an enzyme with protease activity the performance of which in creating several cancers has been reported up to now. With respect to the relationship between the active form of this enzyme and occurrence of cancer, in the present study, we decided to assay the plasma level of this enzyme in recuperating or aggravating and metastasis of the breast cancer. In this study, MMP-9 activity was measured by gelatin quantitative zymography in the euglobulin plasma of 98 patients in two steps of diagnosis and after treatment of cancer. From the 80 patients with positive response to treatment, in 76 persons, the MMP-9 significantly decreased after treatment compared to the time of diagnosis. Whereas in 4 patients, the MMP-9 plasma level did not show any change before and after the treatment. Also in 18 patients with recurrence, (6 persons with early breast cancer and 12 persons with metastasis to other tissues) this enzyme level increased, compared with the time of diagnosis. Our results show a positive correlation between plasma MMP-9 activity and the treatment or metastasis to the other tissues. According to our findings, plasma MMP-9 level can be used as a useful factor for investigating the reaction status of breast cancer patients to the treatment.