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Updated: Apr 30, 2026
Building Up a High-throughput Screening Platform to Assess the Heterogeneity of HER2 Gene Amplification in Breast Cancers
Published on: December 5, 2017
HER2 mutation status in Japanese HER2-negative breast cancer patients
Yumi Endo1, Yu Dong1, Nobuyasu Yoshimoto1
1Department of Oncology, Immunology and Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya.
Objective:
Human epidermal growth factor receptor 2 (HER2) gene amplification is a major therapeutic target in breast cancer, and has been introduced as a predictive biomarker to identify patients who may benefit from therapy with anti-human epidermal growth factor receptor 2 agents. Human epidermal growth factor receptor 2 somatic mutations have been reported in patients without human epidermal growth factor receptor 2 gene amplification. Since these are activating mutations, these patients may also benefit from human epidermal growth factor receptor 2-targeted drugs.
Methods:
In this study, we searched for human epidermal growth factor receptor 2 mutations in a group of 286 Japanese breast cancer patients with human epidermal growth factor receptor 2-negative tumors. The activating mutations of human epidermal growth factor receptor 2 identified were analyzed by direct Sanger sequencing of two major areas: the extracellular domain at 309-310 and the kinase domain between 755 and 781.
Results:
Two tumors were found to have a human epidermal growth factor receptor 2 somatic mutation; one with I767M mutation and another with D769Y. No mutation was observed in the extracellular domain. One of these patients with human epidermal growth factor receptor 2 mutation recurred early with liver metastasis.
Conclusions:
Better knowledge of human epidermal growth factor receptor 2 mutation status will help us to choose personalized molecular targeted therapy for use in human epidermal growth factor receptor 2-negative Japanese breast cancer patients.
Insights
Activating human epidermal growth factor receptor 2 (HER2) mutations were found in HER2-negative breast cancer patients. These mutations may respond to HER2-targeted therapies, offering new personalized treatment options for this patient group.
Area of Science:
- Oncology
- Genetics
- Molecular Biology
Background:
- Human epidermal growth factor receptor 2 (HER2) gene amplification is a key target in breast cancer treatment.
- HER2 mutations can occur in patients without gene amplification and may respond to targeted therapies.
Purpose of the Study:
- To investigate HER2 mutations in Japanese breast cancer patients with HER2-negative tumors.
- To identify potential new therapeutic targets in HER2-negative breast cancer.
Main Methods:
- Screened 286 Japanese breast cancer patients with HER2-negative tumors for HER2 mutations.
- Analyzed activating HER2 mutations in the extracellular and kinase domains using Sanger sequencing.
Main Results:
- Identified two cases with HER2 somatic mutations (I767M and D769Y).
- No mutations were detected in the extracellular domain.
- One patient with a HER2 mutation experienced early recurrence with liver metastasis.
Conclusions:
- Understanding HER2 mutation status is crucial for personalized therapy selection.
- HER2-targeted treatments may benefit HER2-negative Japanese breast cancer patients with specific mutations.
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