Glycosylation of proteins in healthy and pathological human renal tissues.

Cancer development is associated with the improper glycosylation of proteins. There are alterations in the synthesis and expression of sugar structures. These changes can be important not only in the early stages of tumour development, but also in the next stages connected with cancer invasiveness and its ability to form metastases. Oligosaccharide structures of glycans in tumours deviate from normal cells. Relatively increased degrees of branching and sialylation of N-glycans, enhanced presentation of short-chain mucin-type O-glycans with sialylation, and alterations in the expression of blood group ABO and Lewis epitopes can be observed. The main aim of our study was to assess changes in the glycosylation of proteins in clear cell renal cell carcinoma. This study was performed on tissues taken from 15 patients. The relative amounts of sugar structures of proteins with molecular mass above 30 kDa in tumour (cancer tissue), intermediate zone i.e. tumour-adjacent tissue, and normal tissue uninvolved by tumour, were determined by ELISA-like test with biotinylated lectins highly specific to examined sugar antigens. A higher expression of all examined structures was revealed in cancer tissue. Increased levels of sialic acid, fucose, T and Tn antigens, compared to healthy renal tissue, were characteristic for clear cell renal cell carcinoma.