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The evolving spectrum of HER2 expression

30 Apr 2024

This content is organized and funded by AstraZeneca. This content is intended for healthcare professionals only. Z4-62768. DOP: March 2024. Any use and distribution of the information contained in this document must be assessed and approved in accordance with regional/local approval processes to ensure compliance with applicable local laws, regulations, codes and AZ policies.

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How do you approach HER2 IHC classification in breast cancer?

HER2 testing in breast cancer patients

Accurately determining HER2 status in breast cancer is crucial to guiding treatment decisions and ensuring that patients receive therapies tailored to their disease. Patients diagnosed with breast cancer receive HR and HER2 biomarker testing to determine HER2 status and inform the treatment decision. Over the years, HER2 testing has evolved to improve the identification of HER2 positive breast cancer, along with significant advances in clinical practice and test standardization that reduce the rate of inconsistency in determining HER2 positive expression1.

HER2 negative patients

A multicentre study found that up to 60% of breast cancers that were classed as HER2 negative had detectable levels of HER22.

Although the range of HER2 expression has been established, clinical interpretation is binary and classed as either positive or negative, based on validated IHC and ISH assays3,4. It’s time to implement a new approach to the assessment of HER2 expression, one that recognizes expression as a spectrum of negative, low, positive and places emphasis on the dynamic nature of HER2 expression throughout the patient journey.

Accurate analysis and interpretation is the key to delivering the most effective treatment strategies that can positively impact patients. Now is the time to re-think what we know about determining HER2 expression.

Download the HER2 report checklist to learn more about HER2 reporting practice and access the pathology report checklist.

Coming soon

Diaceutics are hosting a Lab Talk, A new perspective on HER2 testing- Evolving the lab practices to match clinical advances, discussing the new perspectives emerging on the HER2 testing landscape and the need for consistent and reliable scoring to optimize performance in the diagnostic process. This session will analyze the clinical utility of HER2 testing, technical considerations (both pre-analytical and analytical), scoring reproducibility and include a Q&A session with Professor Dr Abeer Shaaban MSc, PhD, FRCPath.

1. Pfitzner BM, et al. Modern Pathol. 2018;31:607-615. 2. Schettini F, et al. NPJ Breast Cancer. 2021;7:1-13. 3. Ahn S, et al. J Pathol Transl Med. 2020;54:34-44. 4. Wolff AC, et al. J Clin Oncol. 2018;36:2105-2122.​