Immunohistochemical Study of Androgen Receptor Expression in Estrogen Receptor-Negative Invasive Breast Carcinoma and its Relation with Clinicopathologic Factors

Abstract

BACKGROUND: Estrogen receptor (ER)-negative breast carcinomas lack the expression of ER and they have no targeted hormone therapies. The androgen receptor (AR) is a newly emerge biomarker. Detecting AR in these tumors may provide a target for future therapies.
 AIM: The aim of the study is to examine the immunohistochemical expression profiles of AR protein in ER-negative invasive breast carcinomas and to assess the relation between AR expression and the clinicopathologic factors such as age, tumor size, tumor grade, tumor type, immunohistochemical type, lymph node status, and Ki67 expression.
 METHODS: Sixty paraffin blocks of ER-negative invasive breast carcinoma cases were stained immunohistochemically by AR. Positive expression was defined as ≥1% nuclear staining.
 RESULTS: AR positivity was detected in 55% of the studied cases. The positive cases were scored by H-score with a median=117, and a range of 3–285 and by Allred score with a median=7, and a range of 3-8. AR is expressed in 60.9% of triple-negative breast carcinoma cases. AR expression was higher in older age, and there were significant positive correlations between the degree of AR expression (AR%, AR intensity, and H-score) and age (p=0.050, 0.007, 0.033, respectively). There was non-significant negative correlation between Ki67% and the degree of AR expression (AR%, AR intensity, H-score, and Allred score). Regarding different histological types, tumor grade, tumor size, lymph node status, and immunohistochemical types, there was no significant difference between AR positive and AR negative cases.
 CONCLUSION: AR is frequently expressed in ER-negative invasive breast carcinoma; especially in older age, and in a large number of triple-negative subtypes. This may give chance to benefit from future AR target therapy. We recommend further research work on AR expression in the special histologic subtypes of ER-negative breast carcinoma and in the triple negative group.