Immunohistochemical expression of androgen receptor and prostate-specific antigen in breast cancer.

AR (androgen receptor) and PSA (prostate-specific antigen) are involved in the pathogenesis of breast cancer, but their role is not clearly defined. The purpose of this study was to analyze by immunohistochemistry the AR and PSA (prostate-specific antigen) expression in 156 female breast carcinomas and to correlate the results with some histopathological parameters, like ER (estrogen receptor), PR (progesterone receptor), HER2/neu, nodal and metastasis status, histological type and grade. ARs and PSA were expressed in 112/156 (72%) and respectively in 61/156 (39%) of cases and we found a positive correlation between AR and PSA expression in breast carcinomas (p<0.0002). We also found an association between the histological type of the tumor and AR (p<0.001), respectively PSA (p=0.01) and between AR and the grade of differentiation (p=0.007) and the nodal status (p=0.02). No correlations were found between the metastasis status and AR or PSA. 47.3% (53/112) of AR-positive cases and 46% (28/61) of PSA-positive cases were ER-negative. High frequency of AR (87.5%) and PSA (75%) expression was found in medullary carcinomas and 53% of lobular invasive carcinomas co-expressed AR and PSA. We found an inverse correlation between HER2/neu and PSA (p=0.05). Although most of the PSA-positive carcinomas were lymph node-negative, well and moderately differentiated, we did not find any statistically significant correlations between these parameters and PSA expression. Our study confirms that ARs are commonly expressed in breast cancer and the expression of PSA and AR are highly correlated. Moreover, all the lobular carcinomas and the majority of medullary carcinomas co-expressed AR and PSA, the majority of AR-positive carcinomas were lymph node-negative, well and moderately differentiated, and large number of ER-negative carcinomas expressed AR and PSA.