Expression of estrogen receptors ER-α, ER-β, androgen receptor (AR) and DAX-1 in human breast. (a–d) Immunohistochemistry of ER-α. (a) Negative immunoreaction in ductal hyperplasia (magnification × 300). (b) Sample of ductal carcinoma in situ (CIS) showing a strong immunolabelling of ER-α in the nuclei of neoplastic cells (magnification × 500). (c) A strong nuclear reactivity to ER-α antibody was observed in samples of infiltrative ductal carcinoma (IDC; magnification × 250). (d) ER-α was observed in the cytoplasm of some cells in infiltrative lobular carcinoma (ILC; magnification × 300). (e–h) Immunohistochemistry of ER-β. (e) Fibroadenoma was always negative to ER-β (magnification × 300). (f) Ductal CIS showing an intense cytoplasmic immunoreaction to ER-β (magnification × 400). (g) Positive reaction to ER-β in the cytoplasm of IDC cells (magnification × 250). (h) ILC showing cytoplasmic reaction to ER-β (magnification × 450). (i–l) Immunohistochemistry of androgen receptor (AR). (i) Negative reaction to AR antibody in hyperplasia (magnification × 300). In CIS (j) (magnification × 400) and IDC (k) (magnification × 200), cytoplasmic immunolabelling of AR was observed. (l) ILC showing cytoplasmic immunostaining of AR (magnification × 200). (m-p) Immunohistochemistry of DAX-1. An intense cytoplasmic reaction with granular pattern was observed in cases from ductal hyperplasia (m) (magnification × 200), CIS (n) (magnification × 600), IDC (o) (magnification × 600), and ILC (p) (magnification × 350). BBD, benign breast diseases.