HER2 Assessment in Upper Gastrointestinal Tract Adenocarcinoma: A Practical, Algorithmic Approach.

Gastric and gastroesophageal junction adenocarcinomas constitute a major health problem. For localized disease, adjuvant treatment is multidisciplinary and usually includes a combination of surgery, radiation and chemotherapy. Recently, trastuzumab (Herceptin) has been approved for the treatment of metastatic upper gastrointestinal (GI) tract (gastric, esophageal, and gastroesophageal) adenocarcinomas. The purpose of this review is to provide pathologists with practical guidance in HER2 assessment of upper GI tract adenocarcinomas in order to accurately identify patients eligible for trastuzumab therapy.