Lectins are
sugar-
binding proteins that bind to specific cellular
carbohydrates, commonly affecting cellular physiology.
Phaseolus vulgaris leucoagglutinin (PHA), ulex europaeus isoagglutinin-I (UEA-I),
wheat germ agglutinin (WGA) and
peanut agglutinin (PNA) are among the most well studied
lectins in various tissues. The purpose of this study was to detect the above
lectins binding sites and so examine alterations in
glycoconjugate expression in neoplastic cells of 52 colorectal
adenomas with various clinicopathologic characteristics and proliferation rates.
Lectin histochemistry was performed in
paraffin sections with and without
neuraminidase treatment. Proliferative fraction was determined by immunolabelling for
Proliferating Cell Nuclear Antigen. PHA was the more frequently positive
lectin in the examined specimens; however, it was simultaneously detected in normal colonic mucosa and so was WGA. The frequency of high grade dysplasia was significantly greater in older patients and in samples with UEA-I positivity without
neuraminidase pretreatment. UEA-I-reactive
adenomas were generally characterized by high cell proliferation rates. A statistical model based on patients age and UEA-I binding without
neuraminidase treatment can generally predict grade of dysplasia in 83% of
adenomas and particularly high grade dysplasia in up to 93% of
adenomas; so, such a model may be potentially useful for the early detection of
neoplasia, for instance in exfoliative cells from the large intestine.