Elucidation of similarities of sugar receptor (lectin) expression of human lung metastases from histogenetically different types of primary tumors.

Selective interplay between proteins and carbohydrates of cellular glycoconjugates offers the potential to mediate physiologically important biorecognition and biosignaling, relevant to metastasis formation. Biotinylated neoglycoproteins were therefore employed as tools to detect endogenous sugar receptors (lectins) in paraffin-embedded sections of 35 lung metastases from different types of primary tumors. The selection consisted of 17 cases of sarcoma, 11 cases of testicular germ cell tumor, 5 cases of adenocarcinoma, 1 case of melanoma and 1 case of adamanthioma. Receptors with specificity to rhamnose, structurally related to galactose, and N-acetyl-D-galactosamine were present in all or clusters of tumor cells in 27 or 26 of 35 cases. Binding of other carbohydrate constituents of glycoconjugates and of heparin was comparatively lower, ranging from 13 out of 35 cases for L-fucose to 21 out of 35 cases for sialic acid. Regardless of the origin of hte metastatic lesions, the proportions of sugar receptor expression of tumor cells in lung metastases were similar, when the two probes with highest overall extent of binding to tissue sections were applied. Although the influence of the identical microenvironment should not be overlooked, tumor cell homing to a certain target organ may supposedly be reflected in similarities of their profile of receptors for neoglycoproteins, carrying the glycohistochemically decisive constituents of naturally occurring glycoconjugates.