Lectin and proteoglycan histochemistry of Merkel cell carcinomas.

Changes in carbohydrate residue expression and in proteoglycan distribution occur during different stages of tumor development and progression. However, few data concerning carbohydrate residue analysis as performed by lectin histochemistry and proteoglycan distribution of Merkel cell carcinoma, a rare malignant tumor of the skin, have been reported. Hence, lectin- and proteoglycan immunohistochemistry was performed on paraffin wax material of 9 cases of Merkel cell carcinomas characterized by cytokeratin and neurofilament immunohistochemistry. The lectin binding pattern of tumor cells varied between lectins with different sugar binding specificities, while within a given nominal sugar specificity intensities were remarkably similar between tumors from different patients. The most intensive reaction was observed using Con A (mannose/glucose-specific) followed by LCA with the same specificity and the N-Acetyl glucosamine-specific lectins (WGA, UDA, CMA), while no fucose binding sites were detected (UEA-I). In addition, N-Acetyl galactosamine residues were only occasionally detected. The lectin binding pattern of Merkel cell carcinoma cells indicated that predominantly N-linked glycans and not O-linked glycans, typical for mucins of most epithelia, were present. Hence these tumor cells were relatively undifferentiated and resembled stem cells more closely than differentiated epithelia. The tumor stroma was especially evaluated in this study and showed a lectin reaction, which was intermediate between the tumor cells and extra-tumoral stroma. For example, the reactions of N-Acetyl galactosamine-specific lectins were intensive in the extra-tumoral stroma but nearly negative in tumor cells, while the lectin reaction of the intra-tumoral stroma was similar to the cellular reaction. These results indicated an influence of tumor cells on the stromal constituents. Antibodies against chondroitin type glycosaminoglycans reacted with the tumor stroma and the pericellular substance around the tumor cells most intensely in - and around the major tumor septae which, in general, were well vascularized. The most intensive immunoreactivity was detected using the chondroitin-6-sulfate antibody. The cellular and membrane-associated reaction for heparan sulfate was less intensive in comparison to epidermal cells. In conclusion the pattern of lectin-binding sites, the high chondroitin(sulfate) specific reactivity and the relatively low intensity of heparan sulfate immunohistochemistry indicate a low degree of differentiation and high malignity of the tumors, which is consistent with the clinical behavior of Merkel cell carcinomas.

Lectin and proteoglycan histochemistry of feline pacinian corpuscles.

We studied carbohydrate residues of glycoproteins and proteoglycans (PGs) in peritoneal Pacinian corpuscles of five adult cats. Terminal monosaccharides of glycoproteins and related polysaccharides were identified by lectin histochemistry and the PGs and glycosaminoglycans (GAGs) by specific antibodies. The most intensive lectin staining reactions indicated an abundance of glycoconjugates with terminal mannose (Man) or sialic acid residues, but no complex-type oligosaccharides were detected within the corpuscles. Terminal fucose (Fuc) and galactose (Gal) residues typical for O-linked mucin-type glycoproteins generally associated with high water binding capacity were also absent. Antibodies against unsulfated chondroitin (C-0-S), chondroitin-4-sulfate (C-4-S), and decorin showed positive reactions in the interfibrillar spaces between the lamellae, around collagen fibers, and around the lamellae of the perineural capsule, especially in the outer parts known to contain Type II collagen. Biglycan showed a preference for the innermost part of the perineural capsule (intermediate layer), known to contain Type V collagen. Collagen V and biglycan are both linked to growth processes. Hyaluronic acid (HA), chondroitin-6-sulfate (C-6-S) chains, and a chondroitin sulfate proteoglycan (CSPG) were co-localized in the terminal glia. The study of carbohydrates with high water binding capacity may contribute to our understanding of the high viscoelasticity of Pacinian corpuscles.

DNA-grading of malignant lymphomas. I. Prognostic significance, reproducibility and comparison with other classifications.

The prognostic significance of the DNA Malignancy Grade (DNA-MG) was tested for 83 malignant non Hodgkin lymphoma patients in comparison with three different subjective morphological classification systems (New Working Formulation for Clinical Usage, Rappaport and Kiel Classification). Monolayer smears prepared from paraffin embedded tissue and imprint smears from fresh cut lymph-nodes were investigated. Feulgen staining was performed automatically. The scalar DNA-MG was determined by rapid interactive DNA-cytometry, using an automatic microscope and a TV-image analysis system. A strong influence of the DNA-MG on length of survival was found. Compared with morphological classification systems, the DNA-MG was of greater prognostic validity as revealed by different statistical tests. Significant differences of survival probabilities between some groups with differences of 0.5 DNA-MG only were found. The interobserver reproducibility of this new prognostic index was found to be 95% within a range of +/-0.4 DNA-MG.