Predictive Value of Syndecan-1 Expression for the Response to Neoadjuvant Chemotherapy of Primary Breast Cancer

Background: The overexpression of syndecan-1 in breast carcinomas correlates with poorer prognosis and an aggressive phenotype. The effect of syndecan-1 expression on tumor response to neoadjuvant chemotherapy was determined in locally advanced breast cancer. Patients and Methods: Semi-quantitative syndecan-1 immunohistochemistry was performed in pre-chemotherapy breast cancer biopsies of 37 patients undergoing high-dose neoadjuvant treatment with cyclophosphamide and epirubicin. Results: 43.2% of breast carcinomas stained positive for syndecan-1. Syndecan-1 expression was more frequent in ductal invasive carcinomas than in other histological types (p=0.062). The pathological response to chemotherapy was decreased in syndecan-1- positive patients: 37.5% of syndecan-1-positive vs. 19% of syndecan-1-negative patients attained pathologically "no change". No syndecan-1-positive patient showed complete remission. Also, a correlation between syndecan-1 immunostaining intensity and response to chemotherapy was observed. Of the responding tumors, none showed strong syndecan-1 expression (Score 3+), whereas 20% of the non- responding tumors were strongly syndecan-1-positive. Conclusion: Syndecan-1-expressing breast carcinomas show a trend towards a decreased response to chemotherapy. The cell surface heparan sulfate proteoglycan syndecan-1 (SDC-1) is predominantly expressed by different epithelia and plays multiple roles in the regulation of cell migration, cell-cell and cell-matrix interactions, growth factor and chemokine activity, and in the modulation of protease activity