- OBJECTIVE: The prognosis for patients with triple negative breast cancer (TNBC) is poor, however, a subset will demonstrate complete pathological response (pCR) to chemotherapy. GATA-3 and AR may be a negative predictors for pCR although it is unclear if these results apply to TNBC. METHODS: Patients diagnosed with TNBC and treated with neoadjuvant chemotherapy were identified. Immunohistochemistry was performed for GATA-3 and AR. Both were scored using a composite of staining intensity and percentage cells stained. The primary outcome was pCR. RESULTS: Twenty-four patients were included and 7 achieved pCR. There was no difference in the pre-chemotherapy tumor size (44±28mm vs. 54±30mm; p=0.764) or lymph node status (86% vs. 71%; p=0.629) between patients with and without pCR. GATA-3 expression was present in 20 cases (83%) while AR was present in 6 cases (25%). No AR expression was seen in 15 cases (63%) with GATA-3 positivity. There was no difference in either GATA-3 (4.3±2.7 vs. 3.6±2.5; p=0.549) or AR (1.4±2.5 vs. 1.1±2.4; p=0.778) expression between patients with and without pCR. CONCLUSIONS: GATA-3 expression is frequent in TNBC even in the absence of AR. However, neither GATA-3 nor AR are associated with pCR after neoadjuvant chemotherapy.