Lectin Histochemical Study of Cell Surface Glycoconjugate in Gastric Carcinoma Using Helix Pomatia Agglutinin

Altered glycosylation of proteins in cancer cells is one of the main processes responsible for anaplasia, invasion and metastatic potential of neoplastic cells. Lectins are nonimmunogenetic compounds which specifically detect certain terminal sugars of glycoconjugates. The aim of the present study was to identify the N-acetylgalactosamine (GalNac) containing glycoconjugates in cancer cells in all grades of gastric carcinoma. Paraffin blocks belong to 30 patients of gastric carcinoma (10 cases from each grade) was collected from pathology file of Ali-Ebn-Abitaleb Hospital in Zahedan during 2005-2007. Prepared sections (5-7μm in thickness) were stained by Alcian Blue, hematoxylin and eosin (H&E) and helix pomatia agglutinin (HPA) conjugated lectin. Lectin diluted up to 10μg/ml in PBS (0.1M, pH=6.8). Lectin reactivity was visualized by 0.03% diaminobenzidine (DAB) solution. Sections were graded according to staining intensity to lectin (0-4+). Although there was some difference for lectin staining intensity between cancer cells in different grades of gastric carcinoma, statistical analysis showed that there was only a significant difference for cancer cells reactivity between histopathological grades of II and III. The pattern of reactivity to HPA lectin were also different from all histopathological grades. It seems that in cancer cells, the amount and distribution of GalNac containing glycoconjugate differ from neoplastic cells of different histopathological grades in gastric carcinoma.