Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, Tianjin's Clinical Research Center for Cancer, West Huanhu Road, Ti Yuan Bei, Hexi District, Tianjin, 300060, China; Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education. West Huanhu Road, Ti Yuan Bei, Hexi District, Tianjin, 300060, China; Department of Breast Cancer Pathology and Research Laboratory, Tianjin Medical University Cancer Institute and Hospital. West Huanhu Road, Ti Yuan Bei, Hexi District, Tianjin, 300060, China. Electronic address: [Email]
BACKGROUND : In androgen-sensitive prostate cancer, androgenic stimulation induces the synthesis of amphiregulin (AREG). Research is lacking on the role of AREG in invasive breast cancer and the co-expression with androgen receptor (AR) status. METHODS : The present study investigated the prognostic role of AREG in invasive breast cancer cases (N = 298) and the co-expression with the AR status as analysed by immunohistochemistry (IHC). RESULTS : The samples were divided into groups according to AREG expression levels: low/no expression (AREGlow/no) and high expression (AREGhigh). As shown by cytoplasmic immunostaining, 46.0% (137/298) of invasive breast cancers were AREGhigh, and 54.0% (161/298) of cases were AREGlow/no. Co-expression of the AR and AREG accounted for 62.4% (186/298) of cases. A Kaplan-Meier analysis revealed that AREGhigh and AR+/AREGhigh decreased patients' overall survival (OS) (P = 0.002 and P = 0.006, respectively) and disease-free survival (DFS) (P < 0.001 and P < 0.001, respectively). In Cox models, AR+/AREGhigh remained an independent prognostic indicator of OS and DFS in invasive breast cancer (hazard ratio [HR], 0.591, 95% confidence interval [CI], 0.407-0.859, P = 0.006; HR, 0.449, 95% CI, 0.236-0.853, P = 0.014, respectively). AREGhigh remained an independent prognostic indicator of OS and DFS in estrogen receptor (ER)-negative tumours (P < 0.05). CONCLUSIONS : This study suggested that AREG and the AR were co-expressed in invasive breast cancer. Thus, AREG and the AR may be valuable prognostic biomarkers in invasive breast cancer and promising therapeutic targets, especially in ER-negative breast cancer.