Clinical importance of androgen receptor in breast cancer patients treated with adjuvant tamoxifen monotherapy
Androgen receptor; Breast cancer; Estrogen receptor; Estrogen receptor-b; Tamoxifen
Background Despite many studies, the clinicopathological importance of the androgen receptor (AR) in breast cancer is not well established, and its significance as an independent predictor of clinical outcome is controversial. A large and systematic study is needed to address these issues. The aim of the present study was to elucidate whether AR has independent clinical value, examining its importance in a large and well-predefined patient group with a long follow-up period and complete clinicopathological data. Methods Archival materials of 403 invasive breast cancers from women treated with adjuvant tamoxifen monotherapy (median follow-up period 11.0 years) were subjected to immunohistochemical study using anti-AR monoclonal antibody. AR expression was compared with established clinicopathological factors, estrogen receptor (ER)-b expression, and clinical outcome. Results AR positivity was correlated with ER-a positivity, progesterone receptor positivity, ER-b positivity, and a lower nuclear grade. Patients with AR-positive carcinomas exhibited a significantly better clinical outcome than those with AR-negative carcinomas (P = 0.0165 for disease-free survival, P = 0.0344 for overall survival). Multivariate analysis did not yield significant differences in clinical outcome according to the AR status, whereas the ER-b status showed significant differences in multivariate analysis. Conclusions Although, and in agreement with previous reports, AR positivity correlated with some established favorable prognostic factors and with ER-b positivity, AR was not an independent predictor of clinical outcome. Controversy regarding the value of AR as an independent predictor of clinical outcome may at least partly reflect the relatively limited power of AR in breast cancer. © The Japanese Breast Cancer Society 2012.
Honma, N., Horii, R., Iwase, T., Saji, S., Younes, M., Ito, Y., & Akiyama, F. (2013). Clinical importance of androgen receptor in breast cancer patients treated with adjuvant tamoxifen monotherapy. Breast Cancer, 20 (4). http://dx.doi.org/10.1007/s12282-012-0337-2