Characterization of glycoconjugates found in granular cell tumors, with special reference to keratan sulfate

Nine granular cell tumors (GCTs) were studied using the immunoperoxidase technique with a mouse monoclonal antibody to keratan sulfate and a polyclonal antibody to S-100 protein. Various lectins and basic dye stains were also employed. Schwannomas benign and a malignant, a neurofibroma, a leiomyoma, two examples of nevus pigmentosus and a congenital epulis were similarly examined to compare the histochemical reactivities. Tumor cells of all the GCTs reacted intensely with the antibodies to keratan sulfate and S-100 protein. Peripheral nerve bundles and other neurogenic tumors showed stained for S-100 protein but not for keratan sulfate. Basic dye stain indicated the presence of sulfated glycoconjugates in GCTs. Lectin stains demonstrated that GCTs were rich in glycoconjugates but the reactivity patterns for 14 lectins differed between GCTs and normal tissue components. None of the lectins used in this study was specific for GCTs. These results indicate that GCTs contain abundant glycoconjugates and that the monoclonal antibody to keratan sulfate may be an immunohistochemical marker for GCT.