Figure 1

(a) CD10 in normal breast: strong staining in myoepithelial cells. (b) Strong reaction in myoepithelial cells of the pre-existing breast ducts and negative tumor stroma. (c) Weak staining: less than 30% of stromal cells positive. (d) Strong staining: more than 30% of stromal cells positive. Immunoperoxidase method, DAB, × 200.