In patients with locally advanced/advanced breast cancer, prognostic pathological markers such as nodal disease, presence of inflammatory breast cancer or poor pathological response and serum biomarkers such as carcinoembryonic antigen, CA15-3, MMP-2, MMP-9, tissue polypeptide antigen, tissue polypeptide-specific antigen, epidermal growth factor receptor and HER2/neu, have been investigated as predictors of clinical or pathological response to chemotherapy (15,16). This evidence concerns the gene MMP9 and breast cancer.