Significance of GATA-3 expression in outcomes of patients with breast cancer who received systemic chemotherapy and/or hormonal therapy and clinicopathologic features of GATA-3-positive tumors

GATA-3 and estrogen receptor (ER) are involved in a positive cross-regulatory loop and are frequently coexpressed in breast cancers. GATA-3 expression was shown to be an independent predictor of overall and disease-free survival in some studies, whereas others showed no difference. However, the studies used different cutoff values for determining GATA-3 positivity and analyzed outcomes in patients who received systemic therapy together with those who did not. We investigated GATA-3 expression and correlated clinicopathologic findings and outcomes in 516 women who received systemic chemotherapy and/or hormonal therapy. Nuclear staining of 1% or greater was considered positive for GATA-3, ER and progesterone receptor (PR). Of 516 cases, 436 (84.5%) were GATA-3+. GATA-3+ tumors were more likely to be grade 1 or 2, ER+, PR+, non-triple-negative phenotypes (all P <.0001), and higher stage (P =.01). ER-/GATA-3+ tumors, compared with ER-/GATA-3- tumors, had worse breast cancer survival (BCS) (P =.02) and a trend for worse overall survival (OS) (P =.05) in univariate analysis. However, there was no difference in OS and BCS between patients who received chemotherapy and/or hormonal therapy among GATA-3-positive and GATA-3-negative groups. GATA-3+ tumors are correlated with lower grade, ER+, PR+, and non-triple-negative phenotypes. Although there was no difference in OS and BCS between GATA-3-positive and GATA-3-negative groups, there was an adverse effect of GATA-3 expression in the ER-negative subgroup of patients who received systemic therapy.