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Updated: May 27, 2026
Building Up a High-throughput Screening Platform to Assess the Heterogeneity of HER2 Gene Amplification in Breast Cancers
Published on: December 5, 2017
Clinicopathological Characterization of HER2-Low-Expressing Triple-Negative Breast Cancer: Distinct Features From
Michiko Kato1, Hiroko Masuda2, Sayuka Nakayama3
1Department of Surgery, Division of Breast Surgical Oncology, Showa Medical University, Shinagawa-ku, Tokyo, Japan; Department of Pathology, Showa Medical University, Shinagawa-ku, Tokyo, Japan.
Triple-negative breast cancer (TNBC) subtypes HER2-low and HER2-zero are biologically distinct. HER2-low TNBC shows AR-like features, while HER2-zero exhibits basal-like, proliferative traits, suggesting different therapeutic strategies may be needed.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Research
Background:
- Triple-negative breast cancer (TNBC) is aggressive with poor prognosis and heterogeneity.
- HER2-low tumors are emerging targets, but their significance in TNBC is unclear.
Purpose of the Study:
- To investigate the clinical and biological differences between HER2-low and HER2-zero TNBC.
- To determine if these subtypes require distinct therapeutic approaches.
Main Methods:
- Retrospective analysis of 195 primary TNBC patients.
- Collected clinicopathological data, including AR, BRCA, Ki-67, PD-L1, and TILs.
- Classified tumors as HER2-low (IHC 1+/2+ and FISH-) or HER2-zero (IHC 0).
Main Results:
- 38% of TNBC cases were HER2-low, 62% were HER2-zero.
- HER2-low tumors had higher rates of apocrine carcinoma and AR positivity.
- HER2-zero tumors showed more BRCA mutations, higher Ki-67, and increased PD-L1 positivity.
Conclusions:
- HER2-low and HER2-zero TNBC represent distinct biological subgroups.
- HER2-low TNBC is enriched in luminal AR-like characteristics.
- HER2-zero TNBC exhibits basal-like, proliferative, and immunogenic features, potentially requiring tailored therapies.
