Immunoexpression of Claudin 4 in Gastric Adenocarcinomas.

Disturbance of the intercellular adhesion system represents a basic biomolecular mechanism in gastric carcinogenesis. Claudin 4 is member of a protein family involved in maintaining homeostasis and epithelial integrity. In this study, we analyzed the immunoexpression of Claudin 4 in 58 cases of gastric adenocarcinomas, in relation to the main histopathological parameters of aggressiveness, the reactions obtained being evaluated through the intensity of the reactions and the number of positive cells. Positive membranous reactions of Claudin 4 were observed in all cases, in tumor cells and some stromal elements, but in some high grade gastric adenocarcinomas also cytoplasmic immunostaining was present. Claudin 4 high scores were associated with tubular, tubulopapillary and hepatoid adenocarcinomas, of low grade and in early stages, aspects that suggest the usefulness of the marker in evaluating the aggressiveness of gastric epithelial tumors.