Published online Sep 21, 2016. doi: 10.3748/wjg.v22.i35.7926
Peer-review started: April 29, 2016
First decision: July 13, 2016
Revised: August 1, 2016
Accepted: August 10, 2016
Article in press: August 10, 2016
Published online: September 21, 2016
Core tip: Numerous studies have broadened our understanding of HER2 as a critical oncogene in many human cancers, including tumors of the digestive system. Due to the increasing importance of HER2 testing in this heterogeneous group of tumors, in this review we seek to outline the current state of knowledge of HER2 alterations in the most common malignancies occurring in the digestive system, to examine the operational implications of HER2 testing as a biomarker and potentially targetable gene, and discuss immediate future perspectives for pathologists and gastroenterologists.