Immunohistochemical detection of laminin in various breast lesions

The distribution of laminin, a structural glycoprotein specific for basement membranes, was studied in 52 breast lesions with antilaminin and the avidin-biotin peroxidase complex method. Laminin was observed within vascular and epithelial basement membranes. It displayed a continuous linear pattern in normal breast tissue, fibrocystic disease and in benign tumors. In malignant tumors, laminin was heterogeneously distributed, with a discontinuous linear pattern. No intracellular laminin staining was detected. Laminin may be a valuable aid in the differentiation between benign and malignant breast lesions. Absence of basement membrane and lack of the linear pattern of laminin at the boundaries of malignant ducts may be of value in exclusion of carcinoma in situ