Histopathologic evaluation of application of labeled neoglycoproteins in primary bronchus carcinoma

Abstract

Neoglycoproteins are readily available conjugates of a histochemically inert carrier protein and histochemically crucial carbohydrate moieties which are covalently attached to the carrier protein by chemical synthesis. Biotinylation renders these conjugates detectable in formalin-fixed, paraffin-embedded tissue sections of human lung cancer by standard staining protocols, thereby localizing endogenous receptors for carbohydrate moieties. Examination of 30 cases of main types of human lung cancer revealed the presence of α-fucosyl-, α-mannosyl-, and α-glucosyl-specific receptors in adenocarcinomas or epidermoid carcinomas with high positivity rates. The extent of the expression of receptors for α- and β-galactosides appeared to be comparatively lower. Within the standard protocol, using a concentration of the biotinylated probes of 10 μg/mL, this panel of probes consistently failed to detect endogenous sugar receptors in ten cases of small cell anaplastic carcinoma of the lung. Whereas none of the sections from the tumor cases bound the sulfated fucan fucoidan, the accompanying inflammatory cells, especially the granulocytes, expressed receptors for the sulfated fucan. Pronounced labeling for macrophages was observed for the α-galactoside-specific probe, whereas no binding to inflammatory cells and pneumocytes was detectable for the β-galactoside-specific probe. The results indicate that expression of endogenous receptors for neoglycoproteins may be useful in discriminating between small cell and non-small cell lung carcinoma and carcinomatous cells from accompanying inflammatory cells.