Prognostic significance of androgen receptor expression in invasive breast cancer: transcriptomic and protein expression analysis

Differential prognostic roles of Androgen Receptor (AR) have been proposed in breast cancer (BC) depending on tumour oestrogen receptor (ER) status. This study aimed to evaluate the prognostic and/or predictive significance of AR expression in invasive BC. In this study AR expression was studied on a large ( n = 1141) consecutive series of early-stage (I–III) BC using tissue microarray and immunohistochemistry (IHC). AR mRNA expression was assessed in a subset of cases. The prognostic impact of AR mRNA expression was externally validated using the online BC gene expression data sets ( n = 25 data sets, 4078 patients). Nuclear AR IHC expression was significantly associated with features of good prognosis including older age, smaller tumour size, lower grade and lobular histology particularly in the ER-positive tumours. AR was associated with ER-related markers GATA3, FOXa1, RERG and BEX1. Negative association was observed with HER2, p53, Ki67, TK1, CD71 and AGTR1. AR Overexpression was associated with longer survival ( p