Exploring the Role of Androgen Receptor Expression in Triple-Negative Breast Cancer: Implications for Targeted Therapy

Background Triple-negative breast cancers (TNBC) account for 12–24% of breast cancer cases. They are common in young females with high-grade and poor prognosis. Androgen receptor (AR) is emerging as a new therapeutic target in TNBC. Methods This retrospective study was undertaken to evaluate the expression of AR by immunohistochemistry in TNBC, to study its relation to potential prognostically significant factors, and to calculate overall survival (OS) & disease-free survival (DFS) in AR-positive and AR-negative cases. Results A total of 78 TNBC cases were studied for expression of AR, of which 17 (22%) showed AR positivity and presented at an older age. Around 10 cases showed metastasis at presentation, with lung being the most common organ involved in AR-negative group with statistical significance(p-0.026). Histologic features like infiltrating borders, Ductal carcinoma in-situ (DCIS), and apocrine differentiation were mostly seen in AR-positive tumors, while multifocality, necrosis, LVI, and Modified Bloom Richardson(MBR) grade 3 were seen frequently in AR-negative tumors. The tumor size was larger in AR-negative tumors with a statistically significant value(p-0.036). A statistically significant value(p-0.037) was found with AR expression and low Ki-67 index, indicating higher disease-free survival. Although overall survival and disease-free survival were better in AR-positive than AR-negative, a statistical significance could not be established owing to the small study population. Conclusion AR expression can be a prognostic factor for disease outcome in TNBC patients, and along with Ki-67 might be useful to sub-classify risk in these patients. Thus, AR can be used as a predictive factor for new targeted treatment in TNBC.