Updates in the Pathology and Therapy of BRCA Germline–Associated Breast Cancer with a Focus on HER2 Amplification

Dong Won Kim, Christian X. Cruz Pico, Emily Forester, Aakash Belsare, Kristen Whitaker, Elias Obeid, Lori J. Goldstein, Richard J. Bleicher, Mary B. Daly, Austin D. Williams

Research output: Contribution to journalReview articlepeer-review


Purpose of Review: Germline pathogenic variants of the breast cancer type 1 or 2 susceptibility genes (BRCA1 or BRCA2) are associated with the majority of hereditary breast and ovarian cancer syndromes (HBOC). The prevalence of human epidermal growth factor receptor 2 (HER2) gene amplification or protein overexpression in BRCA1/2-associated breast cancers is low. Simultaneous BRCA1/2 pathogenic variants and HER2 alterations confer a poor prognosis. The purpose of this review is to evaluate the recent literature characterizing the concurrent presence of BRCA1/2 and HER2 alterations in breast cancer patients, current management, associated outcomes, and potential opportunities for novel therapeutic approaches. Recent Findings: Simultaneous BRCA1/2and HER2 alterations are uncommon, reporting a prevalence of up to 10% in BRCA1 and 13% in BRCA2-associated breast cancers. Available prognostic data is limited, with some series reporting lower invasive disease-free survival (iDFS) and overall survival (OS) in HER2-positive BRCA1/2-associated breast cancers compared to other tumor phenotypes. Current therapeutic guidelines in the non-metastatic setting recommend the combination of a cytotoxic regimen with HER2-directed therapy. BRCA1/2-mutated breast cancers are susceptible to platinum-based agents and poly(ADP-ribose) polymerase (PARP) inhibitors. Preclinical data shows increased antitumor response with HER2-targeted therapy in HER2-positive BRCA2-mutated cancer cell lines. These findings open the opportunity for combinatorial targeted therapies including anti-HER2 agents, PARP inhibitors, and/or platinum-based chemotherapy. Given that most BRCA-associated cancers are not HER2-amplified, treatment strategies for HER2-low breast cancer could also have applications to patients with BRCA pathogenic variants. Summary: Although available data on HER2 and BRCA1/2 co-alterations in breast cancer is limited, encouraging preclinical and clinical findings could potentially guide trials with novel combinatorial therapies.

Original languageEnglish
Pages (from-to)364-370
Number of pages7
JournalCurrent Breast Cancer Reports
Issue number4
Early online dateAug 11 2023
StateE-pub ahead of print - Aug 11 2023


  • BRCA
  • Breast cancer
  • Diagnosis
  • HER2
  • Prevalence
  • Therapies
  • Treatment


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