Figure 1: MSF expression in breast tissues. Paraffin-embedded tissues were stained with MSF-specific antibody and counter-stained with haematoxylin. Brown colour denotes positive staining. A. Histologically normal breast tissue from a non-tumour patient (NB). No MSF expression in the normal breast lobules or associated stroma. High background in the extracellular matrix of the interlobular stroma, but not in the intralobular stroma. B. Histologically normal breast tissue from the excision marginof a breast carcinoma (NB-T). MSF-positive lobular epithelium, negative stromal cells. C. Normal/benign breast lobule from a patient with fibrocystic change (B). Positive staining in the lobular pithelium, associated fibroblasts and vessels. D. Benign breast tumour, fibroadenoma (B). Positive staining in the tumour epithelium, fibroblasts and vessels. Mostly negative inflammatory cells E. Ductal carcinoma in situ (DCIS). Homogeneous epithelial staining. F. Malignant breast tumour, infiltrating lobular carcinoma of pleomorphic type (T). Heterogeneous epithelial staining. Original magnification x200 (A, B, D, E, F) and x400 (C).