Resolving tumor microenvironment heterogeneity to forecast immunotherapy response in triple-negative breast cancer

Shihao Sun1, Shuang Chen2, Kaiyuan Li3

  • 1Department of Breast Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.

Frontiers in Oncology
|September 4, 2025
PubMed
Abstract

Insights

BRCA1 status influences the tumor microenvironment in triple-negative breast cancer (TNBC). This study identifies ISG15 as a potential biomarker for predicting immunotherapy response in TNBC patients.

Area of Science:

  • Investigating the tumor microenvironment in triple-negative breast cancer (TNBC).
  • Utilizing multi-omics data integration for comprehensive analysis.
  • Exploring the role of BRCA1 mutations in immunotherapy response.

Background:

  • Triple-negative breast cancer (TNBC) immunotherapy outcomes remain suboptimal.
  • BRCA1 mutations are linked to immunotherapy response, but clinical results are limited.
  • Understanding TNBC heterogeneity is crucial for improving treatment efficacy.

Purpose of the Study:

  • To elucidate the impact of BRCA1 status on the TNBC tumor microenvironment.
  • To identify novel biomarkers and cellular phenotypes associated with immunotherapy response.
  • To develop a predictive model for immunotherapy response in TNBC.

Main Methods:

  • Integration of spatial, single-cell, and bulk RNA sequencing data.
  • Multi-scale analysis to identify cancer-associated fibroblast (CAF) phenotypes and biomarkers.
  • High-resolution, label-free proteomics for protein-level validation.
  • Machine learning pipeline for constructing a predictive system for immune checkpoint inhibitor (ICI) response.

Main Results:

  • BRCA1 wild-type TNBC exhibits increased T-cell exhaustion and dendritic cell tolerance compared to BRCA1 mutant.
  • Identification of a MEG3+ pre-CAF subgroup using pseudo-time analysis.
  • ISG15 emerges as a potential immunoregulatory biomarker.
  • A predictive model shows promise in forecasting immunotherapy response.

Conclusions:

  • TNBC exhibits significant cellular heterogeneity.
  • ISG15 is a candidate biomarker for predicting immunotherapy response in TNBC.
  • An ISG15-based predictive system offers a potential framework for forecasting ICI response.