Searching for the face of neoplasia

Modifications of blood group antigens are known to occur in neoplastic tissues of the gastrointestinal tract. We had used lectins, naturally occurring proteins used as molecular probes of carbohydrate structure, to identify a marker of premalignant epithelium in the colon. We used a similar approach to study metaplastic and neoplastic epithelium in the upper gastrointestinal tract, with an emphasis on Barrett's esophagus. The carbohydrate structures (i.e., the glycoconjugates) present faithfully reflected the morphological features, rather than the anatomical location, of each tissue. Of note, only minor modifications in carbohydrate structure were seen in low-grade dysplasia, whereas more distinct changes were seen in high-grade dysplasia and adenocarcinoma. This approach provides insight into the biochemistry and metabolism occurring with disordered maturation of the epithelial cell. The aim of this type of investigation is to develop sensitive markers of earlier neoplasia in the gastrointestinal tract.