Expression of androgen receptor in breast cancer and its significance as a prognostic factor.

BACKGROUND Breast cancer is an extraordinarily hormone-dependent tumor. This study was to evaluate androgen receptor (AR) status and its significance in breast cancer in Chinese women. METHODS Three hundred and thirty-five consecutive cases of invasive ductal breast carcinoma, 34 ductal carcinoma in situ (DCIS), and 82 DCIS adjacent to invasive tissues were involved in this study. The expression of AR was analyzed by immunohistochemistry and compared with patient outcome, and its implications were evaluated in five molecular subgroups of invasive ductal carcinoma (IDC) and in DCIS lesions. RESULTS AR expression was related to that of estrogen receptor (P < 0.001) and progesterone receptor (P = 0.035) but not correlated with the other conventional parameters. AR retained independent prognostic significance (hazard ratio 0.309, 95% confidence interval, 0.192-0.496; P < 0.001). The majority (61.0%) of basal-like breast cancers showed loss of AR expression (P < 0.001), which had poor prognosis. The percentage of AR-positive cases was significantly higher in DCIS adjacent to IDC group than in pure DCIS and IDC groups (93.9%, 79.4%, and 72.5%; P = 0.046 and P < 0.001, respectively). CONCLUSIONS Our data suggest that AR may provide another specific definition of breast cancer subtypes and reveal a potential role in DCIS progression. These findings may help develop new therapies.