ERBB2 and breast cancer: In contrast with breast cancer, for which HER2-targeted therapies have been established for a long time with five treatment options approved by the US Food and Drug Administration, for gastric, GEJ, or esophageal cancers, less is known about the prognostic role of HER2, and therapeutic options are limited to trastuzumab in combination with chemotherapy.26 Our results suggest there is a clinical benefit in patients with indications beyond gastric or GEJ cancers.