Figure 3

Myoepithelial cell layer disruptions and overlying larger estrogen receptor (ER)-negative cell clusters (> 15 cells) in ER-positive neoplastic and hyperplastic ducts. All sections were immunostained for ER (brown) and smooth muscle actin (red). (a) Ductal carcinoma in situ, 100×; (b) two small ducts with atypical intraductal hyperplasia, 100×; (c) a hyperplastic duct, 100×; (d) two hyperplastic ducts, 200×. Myoepithelial cell layer disruptions and ER-negative cell clusters are identified with arrows.