HER2 in Gastric Cancer: Biological Significance and Practical ConsiderationsJalikis, Florencia MD; Swanson, Paul E. MD; Yeh, Matthew M. MD, PhDPathology Case Reviews: September/October 2014 - Volume 19 - Issue 5 - p 245–251 doi: 10.1097/PCR.0000000000000053 Case Reviews Buy Abstract Author InformationAuthors Article MetricsMetrics Gastric and gastroesophageal adenocarcinomas are common neoplasms usually associated with a poor prognosis. Despite improvement in the diagnosis of early gastric cancer, the majority of patients will be diagnosed with advanced disease. For these patients, therapeutic options are limited, with chemotherapy being the most effective treatment. It has been reported that 20% of gastric cancers and 33% of gastroesophageal adenocarcinomas express HER2. In these patients, the addition of trastuzumab to standard chemotherapy regimens may improve survival. Therefore, accurate determination of HER2 status in gastric and gastroesophageal adenocarcinoma is now an essential element of management. Current methods for the detection of HER2 overexpression/amplification include immunohistochemistry and in situ hybridization techniques (both fluorescent and chromogenic). To correctly interpret these studies, the pathologist should become familiar with current testing recommendations and potential interpretation pitfalls. These form the basis of the following review. From the Department of Pathology, University of Washington School of Medicine, Seattle, WA. Reprints: Matthew M. Yeh, MD, PhD, 1959 NE Pacific St, Box 356100, Seattle, WA 98195. E-mail: email@example.com. The authors have no funding or conflicts to declare. © 2014 by Lippincott Williams & Wilkins.