Myoepithelial cell layer disruptions and overlying estrogen receptor (ER)-negative cell clusters in normal and hyperplastic appearing ducts. All sections were immunostained immunostained for ER (brown) and smooth muscle actin (red). (a)–(c) Normal appearing ducts, 400×; (d)–(f) hyperplastic ducts, 400×. Myoepithelial cell layer disruptions and ER-negative cell clusters are identified with arrows.
Man et al. Breast Cancer Res 2003 5:R231-R241 doi:10.1186/bcr653