Epithelial cell adhesion molecule (EpCAM) overexpression is correlated with malignant potentials of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas

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Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas exhibit a wide range of histopathological variation. Epithelial cell adhesion molecule (EpCAM) is a 40 kDa type I membrane protein that is known to be highly expressed in epithelial carcinomas. In this study, we examined immunohistochemical expression of EpCAM in the pancreatic IPMNs in order to clarify its clinicopathological significance. We analyzed 51 cases of surgically resected IPMNs: 32 cases of adenoma; 6 cases of non-invasive carcinoma; 8 cases of minimally invasive carcinoma; and 5 cases of invasive carcinoma. Additionally, these 51 cases were classified into four phenotypes (gastric, intestinal, pancreatobiliary and oncocytic). EpCAM overexpression was found in 16 (31.4%) of the tumor samples. We found five predictive factors of malignancy using the univariate analysis as follows; serum CA19-9 level, main pancreatic duct diameter, presence of mural nodule, phenotype and EpCAM overexpression. In the multivariate analysis, only EpCAM overexpression was identified to be independently associated as a predictive factor for malignancy (odds ratio, 11.039; 95% confidence interval, 1.877-64.919; P-value, 0.008). Our study is the first report to demonstrate that EpCAM overexpression is an independent factor for malignancy; therefore, EpCAM overexpression is thought to be a novel predictor of malignant IPMNs.