Expression of Ep-CAM in intestinal metaplasia, gastric epithelial dysplasia and gastric adenocarcinoma

Background: The epithelial cell adhesion molecule (Ep-CAM) is widely associated with human carcinomas. However, the expression and distribution of Ep-CAM in gastric premalignant and malignant lesions are not well known. Method: We examined the expression of Ep-CAM in 99 cases of gastric adenocarcinoma and associated uninvolved gastric mucosa, 39 cases of gastric biopsy specimens with chronic gastritis (CG) with or without intestinal metaplasia (IM) (25 cases) and gastric epithelial dysplasia (GED) (14 cases) by immunohistochemical staining. In gastric adenocarcinoma, we correlated the results with established prognostic factors, and in IM and GED, with Hepatocyte paraffin 1 (Hep Par 1) expression, introduced as a marker of IM. Results: Ep-CAM overexpression was noted in 0% of normal epithelia, 93.9% of IM, 42.9% of GED and 34.3% of adenocarcinoma. The average immunostaining score of normal epithelia, IM, GED and gastric adenocarcinoma was 0.14 (+/- 0.26), 7.18 (+/- 1.93), 5.67 (+/- 2.29) and 4.09 (+/- 1.89), respectively. There were significant differences among the groups. Ep-CAM overexpression in adenocarcinoma correlated with Lauren classification and histologic grade, but not with tumor stage, lymph node metastasis and p53 expression. Both Ep-CAM and Hep Par 1 expressions showed excellent correlations with IM (P < 0.0001). Ep-CAM expression was consistently observed in all cases of GED with a moderate to strong intensity, and Hep Par 1 weakly in 10 out of 14 cases. Conclusion: Our findings suggest that increased levels of Ep-CAM represent an early event in gastric carcinogenesis, and seem to have a specific relation with the development of IM as a morphoregulatory molecule. (C) 2005 Blackwell Publishing Asia Pty Ltd.