Increased galectin-3 expression in gastric cancer: Correlations with histopathological subtypes, galactosylated antigens and tumor cell proliferation

Galectin-3 represents an endogenous galactoside-binding lectin which may be involved in tumor cell adhesion and proliferation. In order to evaluate it s biological significance in human gastric cancer, we investigated its expr ession in the stomach of a large series of patients (n = 193) by immunohist ochemical staining with the monoclonal antibody Mac-2. Compared to normal t issues, primary gastric adenocarcinomas showed a slight increase in galecti n-3 expression. However, there was no correlation of membrane-bound and cyt oplasmic galectin-3 with histopathological differentiation parameters (acco rding to the WHO and Lauren classifications) or tumor progression (as docum ented by pTNM staging). Nuclear galectin-3 reactivity was significantly str onger in diffuse-type cancer compared to the intestinal-type tumors. Galect in-3 binds to terminal GalNAc alpha(1-3) bound to polylactosamine chains an d related glycotopes. Therefore, the strong coexpression of membrane/cytopl asmic galectin-3 with Griffonia simplicifolia agglutinin (GSA I) binding si tes (Gal alpha 1-3Gal-, GalNAc alpha-) on carcinoma cells seems to be inter esting. On the other hand, nuclear galectin-3 immunoreactivity did not corr elate with the incidence of Ki-67-positive tumor cells. A prognostic value of galectin-3 regarding patient survival could not be established. Copyrigh t (C) 2000 S. Karger AG, Basel.