Endogenous sugar-binding proteins in human breast tissue and benign and malignant breast lesions

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Abstract
Binding of carbohydrate moieties was detected in tissue sections of human breast by employing two types of labeled ligands: neoglycoproteins (chemically glycosylated, histochemically inert carrier protein) and desialylated naturally occurring glycoproteins. Paraffin-embedded, formalin-fixed sections from 40 benign and malignant breast lesions were examined for the presence and distribution of endogenous sugar receptors, employing a panel of 13 biotinylated neoglycoproteins, representing carbohydrates commonly found in naturally occurring glycoconjugates, and four biotinylated glycoproteins. Benign and malignant breast lesions revealed staining with mannosylated carrier neoglycoprotein in comparison to normal breast. A mixed pattern of staining localization and intensity was seen for different types of malignancy with this neoglycoprotein. Similarly, receptors for lactose and N-acetyl-glucosamine could only be detected within the cytoplasm for certain types of malignancy. Their nuclear localization, however, could also be seen in normal breast specimens. The extent of staining with different glycoproteins, containing different types of galactoside-terminal sugar chains, also appeared to differ between various types of breast cancer. The detection of endogenous sugar receptors by neoglycoproteins is proposed to contribute to an understanding of malignancy-associated alterations in the structure of their potential physiological ligands, the glycoconjugates. Changes in the structure and abundance of such glycoconjugates have commonly been detected with the use of plant lectins in histopathologic studies.