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Updated: Aug 28, 2025
Building Up a High-throughput Screening Platform to Assess the Heterogeneity of HER2 Gene Amplification in Breast Cancers
Published on: December 5, 2017
HER2-low inflammatory breast cancer: Clinicopathologic features and prognostic implications
Paolo Tarantino1, Samuel M Niman2, Timothy K Erick3
1Medical Oncology, Dana-Farber Cancer Institute, Boston, MA, USA; Breast Oncology Program, Dana-Farber Brigham Cancer Centre, Boston, MA, USA; Harvard Medical School, Boston, MA, USA; Division of New Drugs and Early Drug Development, European Institute of Oncology, IRCCS, Milan, Italy; Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy.
HER2-low expression is not a distinct subtype in inflammatory breast cancer (IBC). Clinicopathologic features and outcomes show marginal differences between HER2-low and HER2-zero IBC when controlling for oestrogen receptor status.
Area of Science:
- Oncology
- Breast Cancer Research
- Biomarker Analysis
Background:
- HER2-low expression is a predictive biomarker for anti-HER2 antibody-drug conjugates.
- Its clinical significance in inflammatory breast cancer (IBC) remains largely unknown.
Purpose of the Study:
- To investigate the clinical significance of HER2-low expression in HER2-negative IBC.
- To compare clinicopathologic features and outcomes between HER2-low and HER2-zero IBC subgroups.
Main Methods:
- Retrospective analysis of 276 HER2-negative IBC patients from December 1999 to December 2020.
- Patients categorized into HER2-low (IHC 1+ or 2+/ISH-) and HER2-zero (IHC 0) groups.
- Comparison of clinicopathologic features, pathologic complete response (pCR), invasive disease-free survival (iDFS), and overall survival (OS) between subgroups, controlling for oestrogen receptor (ER) status.
Main Results:
- HER2-low tumors were found in 54% of stage III and 39% of stage IV IBC.
- ER-expressing tumors were more frequent in HER2-low versus HER2-zero stage III IBC (65% vs. 38%).
- No significant differences in pCR, iDFS, or OS were observed between HER2-low and HER2-zero IBC when controlling for ER status.
Conclusions:
- HER2-low and HER2-zero IBC show marginal differences in features and outcomes when ER status is considered.
- These findings do not support defining HER2-low as a distinct subtype of IBC.
- Further research may clarify the role of HER2-low in specific IBC contexts.
