Significance of cellular distribution of ezrin in pancreatic cystic neoplasms and ductal adenocarcinoma

Hypothesis: Pancreatic cystic neoplasms and ductal adenocarcinoma manifest diverse clinical features and prognoses, which might be related to cellular distribution of ezrin modulated through various trophic molecules. Design: Laboratory investigation and retrospective analysis. Setting: Medical school-affiliated university hospital. Patients and Methods: Patients with solid pseudopapillary tumor (SPT) (n = 12), mucinous cystic neoplasm (MCN) (n= 18), intraductal papillary mucinous tumor (IPMT) (n = 18), and ductal adenocarcinoma (PA) (n = 73) of the pancreas were studied. Expression of epidermal growth factor (EGF) and its receptor (EGFR) and ezrin were determined using immunohistochemistry. Epidermal growth factor receptor and ezrin expression in sodium butyrate (SB)-treated PA cell line PANC-1 was determined using immunocytochemistry. Messenger RNA expression of ezrin in the PANC-1 cell line treated with SB was determined using reverse transcriptase-polymerase chain reaction. Multivariate analysis of survival of patients with PA was performed. Results: None of 12 SPTs displayed synchronous expression of EGF and EGFR, while all 3 malignant SPTs displayed membranous ezrin expression. One of 18 MCNs displayed synchronous expression of EGF and EGFR, while 4 of 6 borderline malignant and 8 of 8 malignant MCNs displayed membranous ezrin expression. Two of 4 borderline malignant and 11 of 11 malignant IPMTs displayed synchronous expression of EGF and EGFR, and all borderline malignant and malignant IPMTs displayed membranous ezrin expression. Less differentiated PA displayed EGF, EGFR, and membranous ezrin expression more frequently compared with more differentiated PA. Epidermal growth factor receptor expression of PANC-1 cells decreased in an SB dose dependent manner, in which PANC-1 cells became more differentiated and membranous ezrin expression of PANC-1 cells decreased correspondingly. Messenger RNA expression of ezrin in PANC-1 cells also decreased in an SB dose dependent manner. Patients with PA with membranous ezrin expression had a poorer prognosis compared with those without (P=.02). Conclusions: Membranous translocation of ezrin might play a role during malignant transformation of SPT, MCN, IPMT, and PA, which are either dependent on (IPMT and PA) or independent of (SPT and MCN) the EGF-EGFR pathway. Membranous ezrin expression represents a prognostic factor for PA.