BACKGROUND: Recent studies have indicated that the response to chemotherapy and 
the prognostic impact of a pathological complete response (pCR) after 
neoadjuvant chemotherapy differ among breast cancer subtypes. Predictors of 
response to chemotherapy and prognostic factors for survival might be different 
in estrogen receptor (ER)-positive breast cancer.
METHODS: Women with Stage II to III ER-positive HER2-negative breast cancer 
treated with anthracycline and taxane-containing neoadjuvant chemotherapy 
between 2003 and 2011 were retrospectively analyzed. Expression of forkhead box 
A1 (FOXA1), B cell lymphoma 2 (BCL2) and microtubule-associated protein tau 
(MAPT) as well as ER, progesterone receptor, HER2 and Ki67 was examined by 
immunohistochemistry in pre- and post-treatment specimens. Factors predictive of 
response to neoadjuvant chemotherapy and distant disease-free survival were 
analyzed.
RESULTS: Tumor grade was positively correlated with Ki67 expression. Expression 
levels of ER were positively correlated with expression levels of HER2, BCL2, 
FOXA1 and MAPT in pre-treatment tumors. The Ki67 labeling index was the only 
factor that was significantly associated with clinical response measured by the 
reduction of tumor volume and pCR. Lymph node status, expression of ER before 
neoadjuvant chemotherapy and expression of FOXA1 after neoadjuvant chemotherapy 
were significantly associated with distant disease-free survival, both by 
univariate and multivariate analyses.
CONCLUSIONS: Patients with ER-positive HER2-negative breast cancer should be 
selected for neoadjuvant chemotherapy. FOXA1 expression could be a prognostic 
marker in ER-positive breast cancer.