Expression of MUC2 in gastric carcinomas and background mucosae

Gastric carcinomas contain elements of both intestinal and diffuse types. Such heterogeneous components may distort the evaluation of the role of the mucin MUC2 in gastric carcinoma. The role of MUC2 expression in background mucosa is not yet clarified.

We analyzed the expression of MUC2 in gastric mucosa and intestinal metaplasia adjacent to the tumoral area and carcinomas (n = 98) using immunohistochemistry. The immunoreactivity was quantified using an immunohistochemical scoring system.

In the intestinal metaplasia adjacent to the tumoral area, MUC2 was detected in 76 (97.4%) of 78 intestinal metaplasia, and MUC2 expression was inversely associated with the depth of wall penetration (P = 0.026) and tumor stage (P = 0.021). Although the expression rate of MUC2 antigens was higher in intestinal-type adenocarcinoma than in diffuse-type adenocarcinoma, a significant correlation with pathologic staging of the TNM system (pTNM staging) and MUC2 expression could not be found in each subtype of gastric carcinomas.

The expression of MUC2 in intestinal metaplasia was higher in tumors of earlier stages. These findings suggest that increased MUC2 expression in intestinal metaplasia in the neighborhood of the carcinomas may play an important role in gastric carcinomas. Further investigations regarding the role of MUC2 expression in gastric carcinoma and background mucosae are necessary.