HER2 Testing in Breast Cancer

Publication Date: June 7, 2023

Key Points

Key Points

Recommendations by the American Society of Clinical Oncology and College of American Pathologists (ASCO/CAP) human epidermal growth factor receptor 2 (HER2) Testing Expert Panel are aimed at improving the analytic validity of HER2 testing and the clinical utility of HER2 as a predictive biomarker for potential responsiveness to therapies targeting the HER2 protein.

HER2 gene amplification assessed by in situ hybridization (ISH) or protein overexpression assessed by immunohistochemistry (IHC) remains the primary predictors of responsiveness to HER2-targeted therapies in breast cancer.

Greater communication among health-care providers (especially pathologists and oncologists) and appropriate infrastructure support for specimen handling and laboratory facilities have led to observed improvements in the analytic performance and accuracy of HER2 testing.

Highlights

...ghlights

...sed patients with breast cancer mu...


...se has a HER2/CEP17 ratio is ≥2.0 but the avera...


...has an average of ≥6.0 HER2 signals/cell wi...


...ase has an average HER2 signals/tumor...


ISH Testing

...sting...

Acceptable (IHC and ISH) Tests

...le (IHC and ISH) Tests...

Reporting Requirements For All Assay Types

...rements For All Assay Types...

Optimal Tissue Handling Requirements

...timal Tissue Handling Requirements...

Optimal Tissue Sectioning Requirements

...imal Tissue Sectioning Requirements...

Optimal Internal Validation Procedure

...Internal Validation Procedure...