Immunohistochemistry localization of Nodal in human breast tissues. Immunohistochemistry staining for Nodal was scored at 10 × and 63 × magnification in samples diagnosed as (A) benign breast disease, (B) non-invasive, and (C) invasive breast cancer. The scores were multiplied to obtain a final Nodal Scoring Index (SI) that ranged from 1 (A) to 9 (C). Nodal staining was generally intracytoplasmic (D) and occasionally detected in the surrounding stroma (E; red arrows). (original objective magnification indicated in each panel).