Background: Glycoconjugates are a class of cell surface glycoproteins, the terminal sugars of which are important indicators of neoplasia and the aberrant biological behavior of cancer cells. Lectins are a class of plant or animal glycoproteins that specifically bind to the terminal sugars of glycoconjugates. The aim of the present study is to identify the presence of L-fucose in cell surface glycoconjugates and extracellular matrix glycoconjugates of cancer cells of different grades of colonic adenocarcinoma.
Methods: Paraffin blocks of colonic adenocarcinoma tissue from 30 patients were collected from the Pathology Department of Khatam Al Anbia Hospital in Zahedan, Iran. Sections, 5-7μm thick, were prepared and stained using hematoxylin and eosin. Sections were graded histopathologically and then stained using the lectin Ulex europaeus agglutinin (UEA, 10μm/mL), which binds specifically to L-fucose, and Alcian blue (pH=2.5). Sections were graded blindly according to lectin staining intensity on a scale of 0-3. Collected data were analyzed using Kruskall-Wallis and Mann Whitney nonparametric tests with SPSS.
Results: Our results show that there is a significant difference in the staining intensity for L-fucose between tumoral cells of different grades of colon carcinoma (p<0.001). Results show that the degree of UEA lectin binding to cancer cells is lower in the cytoplasm and nucleus and higher in the extracellular matrix in tumors, with the degree increasing with histopathological grade. Furthermore, staining intensity differs in different portions of cancer cells.
Conclusions: The increased staining intensity of L-fucose in the extracellular matrix of colon carcinoma is a reflection of the aberrant protein glycosylation pathway in neoplasia.