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Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. May 21, 2016; 22(19): 4619-4625
Published online May 21, 2016. doi: 10.3748/wjg.v22.i19.4619
HER2 testing in gastric cancer: An update
Lucas Faria Abrahao-Machado, Cristovam Scapulatempo-Neto
Lucas Faria Abrahao-Machado, Cristovam Scapulatempo-Neto, Department of Pathology, Barretos Cancer Hospital, Barretos, SP 14784-400, Brazil
Author contributions: Abrahao-Machado LF performed research, developed and wrote the overall manuscript; and Scapulatempo-Neto C contributed by critically reviewing the manuscript for important intellectual content.
Conflict-of-interest statement: The authors declare no conflicts of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Lucas Faria Abrahao-Machado, MD, Department of Pathology, Barretos Cancer Hospital, Rua Antenor Duarte Villela 1331, Barretos, SP 14784-400, Brazil. lucasfariamachado@yahoo.com
Telephone: +55-17-33216600-6860 Fax: +55-17-33216600-7117
Received: January 19, 2016
Peer-review started: January 21, 2016
First decision: February 18, 2016
Revised: March 2, 2016
Accepted: March 30, 2016
Article in press: March 30, 2016
Published online: May 21, 2016
Processing time: 118 Days and 11.4 Hours
Abstract

Human epidermal growth factor receptor 2 (HER2) overexpression is increasingly recognized as a frequent molecular abnormality in gastric and gastroesophageal cancer. With the recent introduction of HER2 molecular targeted therapy for patients with advanced gastric cancer, determination of HER2 status is crucial in order to select patients who may benefit from this treatment. This paper provides an update on our knowledge of HER2 in gastric and gastroesophageal cancer, including the prognostic relevance of HER2, the key differences between HER2 protein expression interpretation in breast and gastric cancer, the detection methods and the immunohistochemistry scoring system.

Keywords: Human epidermal growth factor receptor 2 testing; Gastric cancer; Immunohistochemistry; Scoring system; Trastuzumab

Core tip: It is clear that human epidermal growth factor receptor 2 (HER2) protein over-expression and gene amplification are much more heterogeneous in gastric cancer compared to breast cancer. Gastric and gastroesophageal tumors require a unique immunohistochemistry scoring system and interpretation expertise. We aimed to clarify the key differences in immunohistochemistry interpretation of gastric cancer, providing a practical update on HER2 testing and scoring.