Androgen Receptor Expression Predicts Decreased Survival in Early Stage Triple-negative Breast Cancer

Background: A subset of triple-negative breast cancer (TNBC) has been reported to express androgen receptor (AR); however, the clinical significance of AR expression in TNBC is unclear.

Methods: We examined immunohistochemical expression of AR in a large cohort of TNBC cases and correlated its expression with clinicopathologic features and clinical outcome.

Results: AR expression was found in 17.7% (87/492) of TNBCs. Positive expression of AR showed significant correlation with older age (p < 0.001), apocrine histology (p = 0.001), and lower histologic grade (p < 0.001). AR was a poor prognostic marker for overall survival (OS) in univariate (p = 0.026) and multivariate (p = 0.008) analyses. In the lymph node-negative (n = 316) subgroup, AR expression was a significant predictor of worse OS and disease-free survival (DFS) in both univariate (p = 0.028 and 0.011) and multivariate (p = 0.024 and 0.01, respectively) analyses. AR expression also was a prognostic factor in pT1 subgroup (OS, p = 0.007; DFS, p = 0.01); however, its prognostic value was not observed in TNBC patients with lymph node metastasis or tumor size larger than pT1.

Conclusions: AR-expressing TNBCs represent a distinct breast cancer subgroup with adverse clinical outcome and AR blockade could be a potential endocrine therapy for these TNBC patients. Evaluation of AR status may provide additional information on prognosis and treatment in patients with TNBC.