Impact of FOXA1 expression on the prognosis of patients with hormone receptor-positive breast cancer.

BACKGROUND: Assessing indications for adjuvant chemotherapy (CT) in patients with hormone receptor (HR)-positive/human epidermal receptor 2 (HER2)-negative breast cancer remains a challenge for oncologists. In this study, we evaluated whether forkhead-box protein A1 (FOXA1) expression was a prognostic and predictive marker for HR-positive breast cancer.

METHODS: FOXA1 expression was analyzed immunohistochemically in 239 primary breast cancers. Associations between FOXA1 expression and clinicopathological characteristics and prognosis were evaluated.

RESULTS: FOXA1 expression was positively correlated with estrogen receptor (ER) (P<0.0001) and progesterone receptor (PR) expression (P=0.0011), and inversely correlated with nuclear grade (P=0.0048) and Ki67 index (P=0.0112). High FOXA1 was associated with longer recurrence-free survival (RFS) in all cases (P<0.0001) and in ER-positive cases (P<0.0001), but not in ER-negative cases. In addition, FOXA1 expression was associated with good prognosis, regardless of the Ki67 index, in HR-positive cases. FOXA1 was an independent prognostic factor on multivariate analysis in all cases and in ER-positive cases. Among HR-positive/HER2-negative cases with high FOXA1 expression, there was no difference in RFS between those given hormone therapy (HT) alone and those given CT plus HT.

CONCLUSIONS: In HR-positive breast cancer, FOXA1 expression was significantly associated with good prognosis. FOXA1 expression may be a useful marker for HR-positive/HER2-negative breast cancer to identify patients with good prognosis who may not require CT.