Research ArticlesEZH2 Expression in Intestinal Neuroendocrine TumorsFaviana, Pinuccia MD*; Marconcini, Riccardo MD†; Ricci, Sergio MD†; Galli, Luca MD†; Lippolis, Piero MD‡; Farci, Fabiola MD*; Castagna, Maura MD§; Boldrini, Laura PhD*Author Information *Department of Surgical, Medical, Molecular Pathology and Critical Area §Unit of Pathology, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa †Department of Oncology ‡General and Urgent Surgery, University Hospital Company of Pisa, Santa Chiara Hospital, Cisanello Hospital, Pisa, Italy The authors declare no conflict of interest. Reprints: Pinuccia Faviana, MD, Department of Surgical, Medical, Molecular Pathology and Critical Area, University of Pisa, Via Roma 57, Pisa 56126, Italy (e-mail: [email protected]). Applied Immunohistochemistry & Molecular Morphology: October 2019 - Volume 27 - Issue 9 - p 689-693 doi: 10.1097/PAI.0000000000000647 Buy Metrics Abstract Neuroendocrine tumors (NETs) arise from the cells present throughout the diffuse endocrine system. These neoplasms were previously regarded as rare, but in fact are increasing in incidence (3.65/100 000 individuals/y). Enhancer of zeste homolog 2 (EZH2) plays a crucial role in cell cycle regulation, and it was reported to be overexpressed in several tumors. The aim of the study was to investigate EZH2 expression, also related with proliferation rate, and p53 expression in NETs of the intestine encompassing a group of tumors primary to the stomach, appendix, small intestine, and colon. The specimens from 33 patients with neuroendrocrine tumors were investigated by immunohistochemistry for EZH2, p53, and Ki-67. Only 10 of 33 (30.3%) cases showed high EZH2 expression. High EZH2 levels significantly associated with elevated proliferation rates (P=0.0012) and with elevated percentage of positive cells for p53 (P=0.011). Our results suggest an association between p53 and the EZH2 pathway in NETs. EZH2 could represent a potential target antigen in cancer immunotherapy. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.