FOXA1 Expression Significantly Predict Response to Chemotherapy in Estrogen Receptor-Positive Breast Cancer Patients.

ABSTRACT

PURPOSE: Most estrogen receptor (ER)-positive breast cancer responds poorly to chemotherapy and no single cost-effective biomarker capable of selecting chemosensitive ones has been found yet. We investigated FOXA1 for its role in predicting chemosensitivity of this subgroup in neoadjuvant chemotherapy settings. METHODS: We reviewed pathologic slides of 123 patients who were diagnosed with ER-positive breast cancer on core needle biopsy and underwent neoadjuvant chemotherapy at our institution between 2002 and 2012. FOXA1 expression and pathologic response were evaluated. We then statistically analyzed FOXA1 expression and its relationship with chemosensitivity. RESULTS: FOXA1 expression before NAC was correlated with poor chemoresponse in ER-positive as well as luminal A and luminal B breast cancer patients (p = 0.002, 0.001, and 0.049 respectively). Significant association between change of FOXA1 staining position after NAC and chemosensitivity also was observed (p = 0.024). Multivariate analysis identified FOXA1 expression before NAC as an independent predictor of chemosensitivity in ER-positive and luminal A breast cancer patients [p = 0.002; relative risk (RR) 0.163; 95 % confidence interval (CI) 0.053-0.500, and p = 0.002; RR 0.055; 95 % CI 0.008-0.353, respectively]. Additionally, change of FOXA1 staining position after NAC was shown to be an independent predictor of chemoresponse in luminal B subtype breast cancer patients (p = 0.012; RR 0.153; 95 % CI 0.035-0.665). CONCLUSIONS: FOXA1 expression can independently predict chemosensitivity of ER-positive breast cancer patients.