Differences in lectin reactivities of cellular glycoconjugates between primary human colorectal carcinomas and their metastases

Abstract

Recent studies have demonstrated that colonic carcinomas consist of heterogeneous populations of cells endowed with different abilities to metastasize. Increasing evidence suggests that cell surface carbohydrates may play an important role in cancer invasion and metastasis. Therefore the binding of five fluorescein isothiocyanate-conjugated lectins to cellular glycoconjugates was analyzed immunohistochemically in paraffin-embedded tissue sections obtained from 16 colorectal carcinomas and their 25 metastases. In positive cases peanut agglutinin (galactose beta 1----3N-acetylgalactosamine), Ulex europeus' agglutinin 1 (alpha-L-fucose), Griffonia simplicifolia agglutinin 1 (galactose), Vicia villosa agglutinin (N-acetylgalactosamine), and G. simplicifolia agglutinin 2 (N-acetylglucosamine) stained apical cell membranes in carcinomatous glands and intraluminal secretions. Nine of 16 primary colorectal carcinomas showed intratumoral heterogeneous cell populations with regard to the lectin binding which resulted in areas of fluorescence-positive and fluorescence-negative carcinomatous glands. Only one liver metastasis showed this intralesional heterogeneity in lectin binding. Nineteen of 25 metastatic tumors produced cellular glycoconjugates which differed in their lectin binding profiles from those made by the majority of the cells in the respective primary colorectal carcinomas. The findings of the present work suggest that many primary colorectal carcinomas consist of phenotypically distinct subpopulations of carcinomatous cells. Most metastatic tumors appeared to result from a selective emergence of carcinoma cells producing glycoconjugates which differed in their lectin-binding profiles from those in their respective primary colorectal carcinomas.