HER2 testing in gastric and gastroesophageal adenocarcinomas

Area of Science:

• Oncology
• Molecular Biology
• Gastroenterology

Background:

• Human epidermal growth factor receptor 2 (HER2) is overexpressed in 10%–35% of gastric and gastroesophageal junction (GEJ) adenocarcinomas.
• The phase III Trastuzumab for Gastric Cancer (ToGA) trial demonstrated improved survival with trastuzumab plus chemotherapy for HER2-positive advanced/metastatic tumors.

Purpose of the Study:

• To review HER2 expression patterns in gastric and GEJ adenocarcinomas.
• To summarize the ToGA trial findings and clinical implications.
• To provide an overview of recommended guidelines for accurate HER2 evaluation in gastric and GEJ cancer.

Main Methods:

• Review of existing literature on HER2 expression in gastric and GEJ cancers.
• Analysis of data from the Trastuzumab for Gastric Cancer (ToGA) trial.
• Examination of current guidelines for HER2 testing and scoring in relevant tumor types.

Main Results:

• Trastuzumab addition to chemotherapy significantly improved survival in HER2-positive advanced/metastatic gastric and GEJ cancer patients.
• HER2 expression patterns and assessment criteria in gastric/GEJ tumors differ from those in breast cancer.
• HER2 testing is now standard for advanced/metastatic disease, though optimal methods are debated.

Conclusions:

• HER2 testing is crucial for guiding treatment decisions in advanced gastric and GEJ adenocarcinomas.
• Specific scoring criteria are necessary for accurate HER2 assessment in these tumors.
• Adherence to recommended guidelines ensures optimal evaluation of HER2 status for patient management.