Expression of androgen receptor and epidermal growth factor receptor in invasive breast cancer: A retrospective study of 1,438 patients from China.

Abstract

e12587 Background: Triple-negative breast cancer (TNBC) is lack of clinically efficient targeted therapies and usually more aggressive with higher rate of distant metastasis and poor overall survival as compared with other breast cancer subtypes. Recent evidence demonstrates that androgen receptor (AR) and epidermal growth factor receptor (EGFR) are involved in the pathogenesis of TNBC. The aim of this study was to explore the expression of AR and EGFR in invasive breast cancer and evaluate the potential of AR and EGFR as biomarkers in TNBC. Methods: In this retrospective study, we analyzed 1438 patients with invasive breast cancer in our hospital from 2015 to 2016. Estrogen receptor (ER) expression, progesterone receptor (PR) expression, Ki-67 index, AR and EGFR expression were detected by immunohistochemical assay. HER2 state was determined by immunohistochemical and FISH assay. χ2 test was used for the analysis. Results: Among 1438 breast cancer patients, 272 (18.9%) cases were TNBC and 1165 (81.0%) cases were non-TNBC. TNBC patients had a low AR expression as compared with non-TNBC patients (29.8% vs 90.2%). There was a significant difference in AR expression in TNBC compared in non-TNBC ( P= 0.000). In contrast, TNBC patients had a high EGFR expression as compared with non-TNBC patients (90.9% vs 21.1%) ( P= 0.000). There was also a significant difference in Ki-67 index in TNBC compared in non-TNBC (89.9% vs 70.1%) ( P= 0.000). AR-positive TNBC patients had a low Ki-67 index expression as compared to AR-negative TNBC (82.7% vs 93.6%). No significant difference of EGFR expression was found between AR-positive TNBC and AR-negative TNBC. Conclusions: AR expression is associated with Ki-67 index and may be as a potential biomarker for targeted therapy in AR-positive TNBC patients.