Androgen receptor expression in breast cancer and its relationship with clinicopathological indicators and molecular subtypes

Objective To investigate androgen receptor (AR) expression in breast cancer tissues and its relationship with clinicopathological indicators and molecular subtypes. Methods Androgen receptor (AR), estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER2) and proliferating cell nuclear antigen Ki-67 expression were evaluated in 200 breast cancer cases by immunohistochemistry assays. Data including patients' age, menstrual status, tumor size, lymph node metastasis, pathology TNM (pTNM) stage and tumor histological grade and other clinical pathological indicators were analyzed. Results The positive rate of AR in breast cancer tissue was 88.5%. It was 67.9% in ER negative breast cancer versus 95.9% in ER positive breast cancer, and 68.4% in PR negative breast cancer versus 96.5% in PR positive breast cancer. AR expression was positively associated with ER and PR expression (P< 0.01, respectively). The positive rate of AR was 94.9% in gradeⅠand gradeⅡbreast cancer, and 74.2% in gradeⅢ. The lower the histological grade was, the higher the positive rate of AR expression was (P< 0.01). The positive rate of AR was 96.3% in Luminal A subtypes and 96% in Luminal B subtypes, and was 87.5% in HER2 positive subtypes, and 44% in triple negative breast cancer (TNBC), and there were significant differences in different molecular subtypes (P< 0.01). Subtypes of Luminal A, Luminal B, and HER2 had higher AR expression rate when compared with TNBC (P< 0.01) with no signifcant difference between the former 3 subtypes. Conclusion AR is widely expressed in breast cancer tissues. Compared with the TNBC, AR expression is higher in Luminal A, Luminal B and HER2 positive breast cancers. However, it is 44% in TNBC subtype. AR could serve as a potential therapeutic target to breast cancer.