Association between Lymph Node Status and Expression Levels of Androgen Receptor, miR-185, miR-205, and miR-21 in Breast Cancer Subtypes

Breast cancer is the most commonly diagnosed cancer among women. Difficulties in treating breast cancer are associated with the occurrence of metastases at early stages of disease, leading to its further progression. Recent studies have shown that changes in androgen receptor (AR) and microRNAs' expressions are associated with mammary gland carcinogenesis, in particular, with the formation of metastases. Thus, to identify novel metastatic markers, we evaluated the expression levels of AR; miR-185 and miR-205, both of which have been confirmed to target AR; and miR-21, transcription of which is regulated by AR, in breast cancer samples (n = 89). Here, we show that the molecular subtypes of breast cancer differ in the expression profiles of AR and AR-associated microRNAs. In addition, the expression of AR and these microRNAs may depend on the expression of PR, ER, and HER2 receptors. Our results show that the possibility of using AR and microRNAs as markers depends on the tumor subtype: a decrease in AR expression may be the marker for the presence of lymph node metastases in patients with HER2-positive subtypes of breast cancer, and disturbance of miR-205, miR-185, and miR-21 expressions may be the marker in patients with a luminal B HER2-positive subtype. Cases with metastases in this type of breast cancer are characterized by a higher level of miR-205 and a lower level of miR-185 and miR-21 in tumor tissues compared to nonmetastatic cases. A decrease in the miR-185 level is also associated with lymph node metastasis in luminal B HER2-negative breast cancer. Thus, the expression levels of AR, miR-185, miR-205, and miR-21 can serve as markers to predict cancer spread to the lymph node in luminal B- and HER2-positive subtypes of breast cancer.