A highly resolved integrated transcriptomic atlas of human breast cancers

Area of Science:

• Oncology
• Genomics
• Immunology

Background:

• The tumor microenvironment (TME) plays a critical role in breast cancer (BC) progression and treatment response.
• Understanding the cellular heterogeneity within the TME is crucial for developing effective therapies.

Purpose of the Study:

• To develop the largest integrated single-cell transcriptomic (scRNAseq) atlas of human breast cancer, encompassing over 600,000 cells from 138 patients.
• To comprehensively characterize the epithelial, immune, and stromal compartments of the BC TME at high resolution.
• To identify TME cell states and immune cell types associated with patient survival and clinical phenotypes.

Main Methods:

• Integration and annotation of publicly available scRNAseq data from human breast cancer patients.
• Detailed subpopulation analysis of immune cells (CD4+, CD8+ T cells, macrophages), stromal cells (endothelial cells, cancer-associated fibroblasts), and cancer epithelial cells.
• Multi-resolution survival analysis across identified subpopulations using The Cancer Genome Atlas (TCGA) and METABRIC datasets.

Main Results:

• A highly resolved atlas of epithelial, immune, and stromal heterogeneity within the BC TME was generated.
• Specific epithelial cell states and immune cell subpopulations conferring a survival advantage were identified.
• Robust associations between TME composition and clinical phenotypes (e.g., tumor subtype, grade) were discovered, underscoring the value of atlas-based analyses.

Conclusions:

• The developed scRNAseq atlas is a significant resource for high-resolution analysis of breast cancer TME heterogeneity.
• This atlas facilitates a deeper understanding of the complex cellular interactions driving breast cancer.
• Findings highlight the importance of integrated, large-scale data analyses for uncovering clinically relevant TME characteristics.