Cytoplasmic EpCAM over-expression is associated with favorable clinical outcomes in pancreatic cancer patients with Hepatitis B virus negative infection.

The identification of reliable prognostic markers that distinguish patients' status and predict therapeutic response can improve the clinical outcomes of pancreatic cancer patients. The epithelial cell adhesion molecule (EpCAM) is known to be highly expressed in cancers and serves as a prognosis factor. Generally, membranous EpCAM expression in cancer cells and its clinical significance are evaluated. However, there is also an evidence of cytoplasmic EpCAM distribution in cancer cells. Hence, we investigated which kind of the immunostaining pattern in pancreatic cancer patients was, and whether membranous or cytoplasmic immunostaining had clinical significance. We determined the cytoplasmic or membranous EpCAM expression by a well-established immunohistochemical staining protocol in 157 pairs of carcinoma and paired adjacent non-tumor pancreatic tissue samples using the EpCAM-specific antibody. Furthermore, we evaluated the relationship between tumoral EpCAM expression of resected specimens and patient's overall survival as well as other biological variables like clinical prognosis by Kaplan-Meier method and χ(2) test. We found that pancreatic cancer patients had expressed higher level of cytoplasmic EpCAM but lower level of membranous EpCAM, and their expressions were significantly correlated. Cytoplasmic EpCAM acted as a favorable prognosis factor on survival time in patients with HBV negative infection. Pancreatic cancer patients with cytoplasmic EpCAM over-expression and negative Hepatitis B virus infection might benefit further from post-surgery chemotherapy. These data suggested a potential role of cytoplasmic EpCAM in predicting patient's prognosis and determining therapeutic strategy.