HER2 evaluation for clinical decision making in human solid tumours: pearls and pitfalls

Area of Science:

• Oncology
• Pathology
• Biomarker Analysis

Background:

• Human epidermal growth factor receptor 2 (HER2)-targeted therapies offer significant clinical benefits in various solid tumors.
• Accurate HER2 status evaluation is crucial for patient selection for these life-saving treatments.

Purpose of the Study:

• To review key considerations for evaluating HER2 status in solid tumors for clinical decision-making.
• To highlight the importance of adhering to specific HER2 biomarker testing guidelines across different organ systems.

Main Methods:

• Discussion of tissue handling and preparation for HER2 biomarker testing.
• Review of pathologist's interpretation of HER2 testing results.
• Examination of HER2 evaluation in breast, gastroesophageal, colorectal, gynecologic, and non-small cell lung carcinomas.

Main Results:

• HER2 scoring criteria vary significantly across different organ systems.
• Understanding unusual patterns of HER2 expression is critical to prevent misinterpretation.
• Adherence to updated HER2 testing guidelines is essential for accurate assessment.

Conclusions:

• Standardized and accurate HER2 evaluation is paramount for guiding HER2-targeted therapy selection.
• Pathologists must be aware of organ-specific criteria and potential pitfalls in HER2 testing.
• This review provides a comprehensive overview to support accurate clinical decision-making.