Biotinylated (neo)
glycoproteins were used to specifically detect endogenous
sugar receptors such as
lectins in sections of formaldehydefixed,
paraffin-embedded tissue from
meningiomas. The histochemical methods used consisted of the application of a
carrier protein and various covalently linked
sugar moieties, available mainly through chemical synthesis, in an optimized standard protocol. They proved valuable in elucidating differential binding patterns within the various
meningioma subtypes. alpha-Fucoside-,
beta-galactoside-, alpha-
mannoside- and beta-xyloside-specific
carbohydrate-binding receptors were detected in all the
tumor subclasses examined, although the levels of expression exhibited pronounced quantitative differences. In addition, differences in the extent of histochemical staining were observed, using a labelled
carrier protein, derived from
N-acetylglucosamine and
mannose-6-phosphate moieties, respectively. Quantitative differences in the reaction intensity were also measured in the respective subtypes. Receptors for
N-acetyl-D-galactosamine were detected only in the analplastic forms, while
glucuronic acid-specific receptors were only present in the
meningotheliomatous meningioma. In contrast to the other types,
malignant meningiomas failed to show cytoplasmic staining with the alpha-
glucoside-specific
maltose-(BSA-
biotin). Distinct differences in the pattern of expression of endogenous
sugar receptors, evaluated by a standard protocol, provided further evidence for a possible additional subtype of
meningioma, the submalignant
meningioma. Our results suggest that labelled (neo)
glycoproteins could be used routinely as tools for assessing the expression of endogenous
sugar receptors in diagnostic neuro-oncology.