Decreased expression of the adhesion molecule desmoglein-2 is associated with diffuse-type gastric carcinoma

Desmoglein-2 (Dsg2) is one of the components of the cell-cell adherence junction. We previously reported that loss of heterozygosity at chromosome 18q12, on which the Dsg2 gene exists, is frequently found in diffuse-type gastric cancers. This study investigated the relationship between Dsg2 expression and diffuse-type gastric cancers. A total of 112 primary tumours resected from patients with gastric cancer were stained with a monoclonal antibody against Dsg2 and examined for correlations between the expression of Dsg2 and various clinicopathological factors, including loss of heterozygosity on chromosome 18q and prognosis. Dsg2 is immunolocalised at cell-cell boundaries in normal gastric mucosa. Loss of Dsg2 expression was observed in 33 of 112 gastric tumours. There was a statistically significant correlation between a decrease in Dsg2 staining and loss of tumour differentiation (P < 0.001), tumour macroscopic feature (P < 0.001) and peritoneal dissemination (P = 0.023), and Dsg2-negative staining was correlated significantly with loss of heterozygosity on chromosome 18q12 (P = 0.001). The prognosis of patients with Dsg2-negative tumours was significantly worse than that of those with Dsg2-positive tumours (log rank, P < 0.01), while multivariate analysis revealed that Dsg2 was not an independent prognostic factor. These findings suggest that decreased expression of Dsg2 is associated with diffuse-type gastric cancers and poor prognosis in gastric carcinoma.