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.