Abstract 2708: E-cadherin expression might be a predictive marker for chemosensitivity in triple-negative breast cancer

Abstract Introduction: Triple-negative breast cancer (TNBC), a subtype of breast tumor with ER negative, PR negative, and HER2 negative, shows a poor prognosis because of a frequent recurrence. Chemotherapy is important for the treatment of recurrent TNBC, however no reliable parameter has been identified for chemo-sensitivity in TNBC. Although E-cadherin is one of markers for chemo-sensitivity in several types of carcinomas, not much of the correlation between E-cadherin expression and chemo-sensitivity is known in TNBC. The aim of this study was to evaluate the significance of E-cadherin in TNBC. Material and Methods: The subjects of this study were 574 patients with primary infiltrating breast ductal cancer. Adjuvant therapy was performed according to the guidelines of breast cancer by NCCN. ER and PR status were assessed by immunohistochemistry. HER2 status was assessed by either immunohistochemistry or fluorescent in situ hybridization. E-cadherin expression was immunohistochemically analyzed by ABC method. E-cadherin expression was semi-quantitatively analyzed according to the percentage of cells showing membrane positivity: 0-10%; 0, 10-30%; 1+, 30-70%; 2+, >70%; 3+. E-cadherin expression was considered positive when scores were ≥2+. Results: Among the 574 breast cancer cases, 123 (21.4%) revealed a triple-negative phenotype. Reduced levels of E-cadherin were observed in 238 (41.5%) of the 574 breast cancer cases. The cases with E-cadherin loss was frequent (90 of 123 cases) in TNBC. Eighty-nine cases of 123 TNBC cases were performed chemotherapy. In 89 TNBC cases with chemotherapy, the prognosis of E-cadherin-negative patients is significantly poor (p<0.01), in comparison with that of E-cadherin-positive patients, while a multiple analysis demonstrated that reduction of E-cadherin expression was not an independent prognostic factor. In contrast, no significant difference of prognosis between E-cadherin positive patients and negative patients was found in 34 TNBC cases without chemotherapy. Conclusion: E-cadherin might be a useful predictive marker for chemo-sensitivity in TNBC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2708.