Differences of HER2 Status by HercepTest and PATHWAY 4B5 Immunohistochemical Assays in Breast Cancer

Key Points

• The aim is to compare HER2 status measurements between two immunohistochemical assays in breast cancer.
• Compared HER2 staining using HercepTest and PATHWAY 4B5 assays.
• Analyzed results to evaluate discrepancies in HER2 levels.
• Examined implications for treatment decisions regarding T-DXd.
• HER2 staining was found to be lower in the 4B5 assay compared to the HercepTest.
• Differences in HER2 status may impact treatment decisions for patients with HER2-ultralow evaluations.