Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Hormone Receptor and HER2 Testing in Breast Cancer: Latest Questions Answered.

Joanna Solarewicz1, Kimberly H Allison1

  • 1Department of Pathology, Stanford Medicine, 300 Pasteur Drive, Stanford, CA, USA.

Surgical Pathology Clinics
|November 12, 2025
PubMed
Summary

Pathologists must update breast cancer biomarker reporting for estrogen receptor (ER) low positive and HER2 low/ultralow cases. These classifications impact treatment decisions, particularly endocrine therapy and eligibility for targeted therapies like trastuzumab-deruxtecan.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Breast Fellows Forum: A Multidisciplinary Core Curriculum Model for Surgical Oncology Fellowships.

Journal of surgical oncology·2026
Same author

Breast Cancer, Version 4.2026, NCCN Clinical Practice Guidelines In Oncology.

Journal of the National Comprehensive Cancer Network : JNCCN·2026
Same author

Navigating Human Epidermal Growth Factor Receptor 2 (HER2) Assessment by Organ Systems: A Guidebook to HER2 Testing in Solid Tumors.

Archives of pathology & laboratory medicine·2026
Same author

HER2 In Situ Hybridization: Validation and Implementation of Brightfield Assay in a US Academic Pathology Laboratory.

Applied immunohistochemistry & molecular morphology : AIMM·2026
Same author

Reporting of both positive and negative concordance is necessary to recognise and investigate bias in digital algorithms.

Journal of clinical pathology·2026
Same author

World Health Organization classification of tumours of the breast 6th edition 2026.

Histopathology·2026

Area of Science:

  • Oncology
  • Pathology
  • Biomarker Analysis

Background:

  • Evolving data necessitate adjustments in breast cancer biomarker interpretation.
  • Estrogen receptor (ER) low positive and HER2 low/ultralow are not distinct subtypes but have significant treatment implications.
  • Accurate HER2 assessment is crucial for targeted therapy eligibility.

Purpose of the Study:

  • To highlight the evolving landscape of breast cancer biomarker interpretation.
  • To emphasize the clinical significance of ER low positive and HER2 low/ultralow classifications.
  • To address the necessity of precise HER2 distinction for treatment guidance.

Main Methods:

  • Review of current breast cancer biomarker interpretation guidelines.
  • Analysis of clinical trial data (e.g., DESTINY-Breast 04/06) defining HER2 low/ultralow categories.
Keywords:
ER low positiveEstrogen receptor (ER)HER2HER2 lowHER2 ultralowProgesterone receptor (PR)

Related Experiment Videos

  • Discussion of diagnostic challenges in HER2 immunohistochemistry (IHC) scoring.

    • Main Results:

    • ER low positive (1%-10%) cancers, while resembling ER-negative tumors, may benefit from endocrine therapy.
    • HER2 low and ultralow status, as defined in key trials, determines eligibility for trastuzumab-deruxtecan in metastatic breast cancer.
    • Distinguishing between HER2 IHC 0 (no staining) and 0+ (some staining) is now clinically essential.

    Conclusions:

    • Pathologists must adapt reporting to reflect the treatment implications of ER low positive and HER2 low/ultralow breast cancer.
    • Precise HER2 IHC scoring is critical for patient selection for novel therapies, despite ongoing concerns about reproducibility.
    • These evolving biomarker interpretations are vital for optimizing breast cancer treatment strategies.