Trefoil peptides, E-cadherin, and beta-catenin expression in sporadic fundic gland polyps: further evidence toward the benign nature of these lesions.

Sporadic fundic gland polyps (FGP) are the most common type of gastric polyps and their pathogenesis is still unclear, although a beta-catenin gene mutation has been described. They are regarded as benign lesions but low-grade dysplasia has been observed, arising more debate on their potential progression to a malignant phenotype. We investigated in FGP the role of factors involved in cell integrity, proliferation, and intercellular adhesion: trefoil peptides (TFF1, TFF2), MIB1, E-cadherin, and beta-catenin. We selected randomly 24 patients with FGP, 24 with normal gastric mucosa and 12 with atrophic gastritis with diffuse intestinal metaplasia (IM-gastritis), all Helicobacter pylori negative. The expression of all factors was examined by immunohistochemistry. In polyps and normal mucosa, TFF1 is expressed only in foveolar compartment whereas in IM-gastritis the signal is reduced in all the compartments. TFF2 is expressed in polyps and normal mucosa, in proliferative and basal compartment, whereas in IM-gastritis the expression is reduced or absent. E-cadherin is expressed in the entire zone: with a medium signal in normal mucosa and polyps, and weaker in IM-gastritis. The beta-catenin's signal in normal mucosa and polyps is moderate-to-intense in proliferative and basal compartments, whereas in IM-gastritis signal is significantly reduced in all the compartments. MIB1 in normal mucosa and polyps is expressed only in proliferative compartment, whereas its expression is stronger in IM-gastritis and involves also basal compartment. In conclusion all the factors considered were normally expressed in FGP and this, especially considered against the findings in IM-gastritis, supports the benign nature of FGP.