Sign in Subscribe
Cancer research

New Insights into Breast Cancer Immunotherapy

Strategic Insights

— 1 min read

Researchers from Peking University Cancer Hospital and Institute have revealed that breast cancers with mismatch repair (MMR) deficiency are highly responsive to immunotherapy, regardless of cancer type. A study analyzing genomic, transcriptomic, and clinical data from over 3000 breast cancer cases found that 1.2% of breast cancers harbored oncogenic somatic MMR alterations. This suggests that some patients with these alterations may benefit from immunotherapy. The findings have significant implications for the treatment of breast cancer.

Key Takeaways:

  • Recent clinical trials have suggested that solid cancers with mismatch repair (MMR) deficiency are highly responsive to immunotherapy, regardless of cancer types.
  • 1.2% of breast cancers harbored oncogenic somatic MMR alterations, with triple-negative breast cancer (TNBC) demonstrating the highest mutation rate at 3.1%.
  • Somatic MMR alterations were significantly associated with microsatellite instability-high (MSI-H) and MMR-related mutational signatures, indicating impaired function of the MMR system.
  • Biallelic inactivation of MMR genes resulted in a more pronounced loss of MMR function compared to monoallelic inactivation.
  • MMR alterations significantly increased the tumor mutational burden (TMB) and neoantigen load in breast cancer, regardless of MSI-H status.
  • The frequency of MMR alterations is highest in TNBC.
  • Immunotherapy may be beneficial for patients harboring MMR alterations in breast cancer.

Statistics:

  • 1.2% of breast cancers harbored oncogenic somatic MMR alterations.
  • 3.1% of triple-negative breast cancer cases demonstrated the highest mutation rate.
  • 3000 breast cancer cases were analyzed in the study.
  • 1.2% to 3.1% is the range of MMR alteration frequency in breast cancer.
  • The TMB load in breast cancer with MMR alterations was significantly higher.

Sources:

  • Comprehensive Analysis of Oncogenic Somatic Alterations of Mismatch Repair Gene in Breast Cancer Patients. Bioengineering, 2025,12(4):426.
  • Peking University Cancer Hospital and Institute.
  • NewsRx. Research from Peking University Cancer Hospital and Institute Has Provided New Study Findings on Breast Cancer (Comprehensive Analysis of Oncogenic Somatic Alterations of Mismatch Repair Gene in Breast Cancer Patients). Immunotherapy Weekly. May 14, 2025; p 468.

Read more