Expression of matrix metalloproteinase 2 and 9 in breast cancer and breast fibroadenoma: a randomized, double-blind study

BACKGROUND: Matrix metalloproteinases (MMPs) 2 and 9 may play an important role in cell proliferation and dissemination of cancer. However, few studies have compared the expression of these proteins between breast cancer and fibroadenoma. MATERIAL AND METHODS: A randomized, double-blind study was carried out in 66 premenopausal women, aged 20-49 years, who had been diagnosed with fibroadenoma or breast cancer. The patients were divided into two groups: Group A, control (fibroadenoma, n=36) and Group B, study (cancer, n=30). Immunohistochemical analysis was performed using tissue samples of fibroadenoma and breast cancer to assess MMP-2 and MMP-9 antigen expression. Cells were considered positive if exhibiting brown cytoplasmic staining. Fisher’s exact test was used to compare the percentage of cases with cells expressing MMP-2 and MMP-9 in control and study groups (p < 0.05). RESULTS: Light microscopy showed a higher concentration of cells with positive cytoplasmic staining for MMP-2 and MMP-9 expression in breast cancer than in fibroadenoma. The percentage of cases with cells expressing MMP-2 in the control and study groups was 41.67% and 86.11%, respectively (p < 0.0009), whereas the percentage of cases with cells expressing MMP-9 in groups A and B was 66.67% and 93.33%, respectively (p<0.0138). MMP-2 and MMP-9 positive expression was significantly higher in moderately differentiated tumors compared to well and poorly differentiated tumors, p <0.005 and p<0.001, respectively. CONCLUSIONS: The current study shows that MMP-2 and MMP-9 protein expression was significantly higher in the breast cancer than in the fibroadenoma and also in moderately differentiated breast cancer.