Androgen Receptor Expression in Triple-negative Breast Cancer and its Relation with Epidermal Growth Factor Receptor, CD 105, and Clinicopathological Parameters

Background: Triple-negative breast cancers (TNBC) are the tumors lacking expression of estrogen receptors, progesterone receptors, and human epidermal growth factor 2. The highest level of androgen receptors (AR) expression belongs to the Luminal androgen receptor subtype. AR is expressed in 70 to 90% of primary breast cancers. The biological role of AR in breast cancer continues to emerge. The overexpression of epidermal growth factor receptor (EGFR) has been previously studied in TNBC, where it was found to be associated with poor prognosis. In the evaluation of neovascularization, CD105 (endoglin) was found to be superior to CD34 and CD31 owing to its greater affinity for endothelial cells in tumor-related angiogenic tissue. We conducted the present work to assess the expression profile of androgen receptor in TNBC cases and its correlation with other clinicopathological parameters, EGFR and CD 105, in order to evaluate its clinical significance. Method: This retrospective study included 50 histologically confirmed breast cancer patients who were proven to be triple-negative based on immunohistochemical study. Formalin-fixed tissue blocks with tumor were chosen for immunohistochemical staining for AR, EGFR, CD105, and Ki 67. Results: Positive AR expression was associated with older age, postmenopausal status, negative nodes, and grade II tumors. AR was inversely correlated with EGFR, while there was no correlation between AR and both Endoglin and Ki 67. Conclusion: AR-positive TNBC may be a subtype of breast cancer with unique characteristics that could make it ideal for antiandrogen endocrine therapy. EGFR and Endoglin's distinct expression indicated that they might be unique biomarkers for targeted therapy and prognosis.