The relationship between androgen receptor, components of tumour microenvironment and survival in breast cancer molecular subtypes

Background: The androgen receptor (AR) pathway has emerged as a potential therapeutic target in breast cancer with increased attention to provide biological insight into triple negative breast cancer (TNBC). The present study assessed the role of AR within the tumour microenvironment in patients with invasive ductal breast cancer. Methods: Immunohistochemical analysis of AR was performed on a breast cancer tissue microarray of 850 patients. These results were correlated with clinicopathological data and cancer specific survival (CSS). Results: Positive AR expression was seen in 75% of luminal A, 70% of B, 47% of Her2 like and 31% of TNBC. AR was associated with invasive grade (p<0.001), estrogen receptor /progesterone receptor (p<0.001), molecular subtypes (p<0.001), necrosis (p<0.001), reduced inflammation (p<0.001), and increased tumour budding (p=0.001). AR was consistently associated with tumour budding in molecular subtypes; luminal A (p=0.022), Her2 like (p=0.035) and TNBC (p=0.034). In TNBC, AR was associated with poor CSS (P=0.013). Conclusion: AR may be an important regulator of tumour budding in breast cancer. AR is a potential prognostic marker and therapeutic target for patients with TNBC