Increased expression of MUC1 and sialyl Lewis antigens in different areas of clear renal cell carcinoma.

Background: Changes in expression patterns of the sialyl Lewis antigens and MUC1 mucin can be considered as markers for the diagnosis of various cancers. However, there are no reports which have been devoted to analysis of differences in the sialyl Lewis antigens and MUC1 expression patterns as potential discrimination markers among different areas of clear cell renal cell carcinoma (ccRCC). The aim of this study was to determine the level of MUC1 and specific Lewis antigens on glycoproteins in three different areas: tumor (cancer tissue), intermediate zone (adjacent to tumor tissue) and normal renal cortex/medulla (uninvolved by tumor).

Methods: Study was performed on renal tissues taken from 30 patients with clear cell renal cell carcinoma. Relative amounts of sugar structures bound with proteins were determined by ELISA-like test with biotinylated lectins or monoclonal antibodies: anti-MUC1 and anti-sialyl Lewis(a/x). The study presented here provides novel information about relationship between MUC1 and sialyl Lewis antigens in the tumor, intermediate zone and noninvolved areas of normal renal tissue distant of tumor.

Results: We have found statistically significant increase of MUC1 and sialic acid linked by α-2,3 bond with galactose in cancer tissue and in intermediate zone comparing to normal renal tissue distant of tumor. Moreover, we observed statistically significant increase of sialic acid linked by α-2,6 bond with Gal/GalNAc and sialyl Lewis(a/x) antigens in cancer tissues only, comparing to normal ones.

Conclusions: MUC1 and sialylated antigens can be involved in renal tumor development and can be considered as potential markers distinguishing normal renal tissue from intermediate zone and from cancer renal cells during ccRCC development.