Immunohistochemical profile of mucins and their expression in precancerous changes of the stomach

Abstract

The aim of this study was to assess the profile of mucins (MUC1. MUC2, MUC5AC) in the intestinal metaplasia (IM) of the gastric mucosa through the immunohistochemical method. Methods: To identity the metaplastic areas in the gastric mucosa, chromoendoscopy was employed using 0.5% solution of methylene blue. The expression of the profile of the mucins was determined using immunohistochemistry with MUC1, MUC5AC, and MUC2 antibodies (clone Ma695, clone CLH2, Ccp58 and CLH5, «Novocastra» Great Britain). Results: In the regions adjacent to the adenocarcinoma and neoplastic modified cells, a visible weak expression of MUC2 and MUC5AC was observed. In the case of complete IM, a visibly maximum MUC2 expression was observed in the goblet cells; thus, the MUC5AC, MUC1, and MUC6 marking were absent in the columnar epitheliocytes with the brush border. In the case of incomplete IM, along with the positive MUC2 markings of the goblet cells, the presence of gastric mucin (MUC5AC) has been observed in 25% of such patients with chronic atrophic gastritis (CAG) having incomplete IM; however, in the columnar epitheliocytes the characteristic occurrence of gastric mucin (MUC5AC) was observed in 100% of the patients while a small amount of MUC2 was recorded in 15% of patients. Conclusion: The MUC5AC expression of the gastric mucins in the columnar epithelial cells and the goblet exocrinocytes marks the formation of the gastrointestinal phenotype viz., incomplete intestinal metaplasia, along with the simultaneous production of the MUC2 by the goblet cells. The decrease with further loss of the protective MUC5AC production by the columnar epithelial cells and goblet exocrinocytes that were found in the regions of severe dysplasia and IM, adjacent to the neoplastic altered cells, may serve as additional criteria of early malignancy of the gastric mucosa.