Lectin binding to normal and malignant breast tissue

The major carbohydrate groups expressed by normal breast epithelium and primary breast cancers were identified by lectins, using an immunoperoxidase method on paraffin sections. All the lectins (pokeweed, lotus, wheatgerm, peanut, helix, bandeiraea 1, soybean and concanavalin A) bound to breast cancer cells with a variable cytoplasmic, luminal surface or intercellular pattern. Not all cancer cells bound lectins, suggesting sub-populations within individual tumours. On normal breast sections all lectins, with the exception of concanavalin A, bound to the luminal surface of the lining epithelial cells or to myoepithelial cells and showed some differences between acinar and ductal epithelium. The main difference in lectin binding between normal and malignant cells was the transition from luminal surface to cytoplasmic binding to lectins by cancers. In addition, quantitative differences were noted, particularly for concanavalin A which bound to cancer cells but not to normal epithelium.