Epithelial Expressed B7-H4 Drives Differential Immunotherapy Response in Murine and Human Breast Cancer

Cancer Res Commun. 2024 Apr 24;4(4):1120-1134. doi: 10.1158/2767-9764.CRC-23-0468.


Combinations of immune checkpoint inhibitors (ICI, including anti-PD-1/PD-L1) and chemotherapy have been FDA approved for metastatic and early-stage triple-negative breast cancer (TNBC), but most patients do not benefit. B7-H4 is a B7 family ligand with proposed immunosuppressive functions being explored as a cancer immunotherapy target and may be associated with anti-PD-L1 resistance. However, little is known about its regulation and effect on immune cell function in breast cancers. We assessed murine and human breast cancer cells to identify regulation mechanisms of B7-H4 in vitro. We used an immunocompetent anti-PD-L1-sensitive orthotopic mammary cancer model and induced ectopic expression of B7-H4. We assessed therapy response and transcriptional changes at baseline and under treatment with anti-PD-L1. We observed B7-H4 was highly associated with epithelial cell status and transcription factors and found to be regulated by PI3K activity. EMT6 tumors with cell-surface B7-H4 expression were more resistant to immunotherapy. In addition, tumor-infiltrating immune cells had reduced immune activation signaling based on transcriptomic analysis. Paradoxically, in human breast cancer, B7-H4 expression was associated with survival benefit for patients with metastatic TNBC treated with carboplatin plus anti-PD-L1 and was associated with no change in response or survival for patients with early breast cancer receiving chemotherapy plus anti-PD-1. While B7-H4 induces tumor resistance to anti-PD-L1 in murine models, there are alternative mechanisms of signaling and function in human cancers. In addition, the strong correlation of B7-H4 to epithelial cell markers suggests a potential regulatory mechanism of B7-H4 independent of PD-L1.

Significance: This translational study confirms the association of B7-H4 expression with a cold immune microenvironment in breast cancer and offers preclinical studies demonstrating a potential role for B7-H4 in suppressing response to checkpoint therapy. However, analysis of two clinical trials with checkpoint inhibitors in the early and metastatic settings argue against B7-H4 as being a mechanism of clinical resistance to checkpoints, with clear implications for its candidacy as a therapeutic target.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • B7-H1 Antigen / antagonists & inhibitors
  • B7-H1 Antigen / metabolism
  • Breast Neoplasms / drug therapy
  • Breast Neoplasms / genetics
  • Breast Neoplasms / immunology
  • Breast Neoplasms / pathology
  • Cell Line, Tumor
  • Epithelial Cells / drug effects
  • Epithelial Cells / immunology
  • Epithelial Cells / metabolism
  • Female
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Immune Checkpoint Inhibitors / pharmacology
  • Immune Checkpoint Inhibitors / therapeutic use
  • Immunotherapy* / methods
  • Mice
  • Triple Negative Breast Neoplasms* / drug therapy
  • Triple Negative Breast Neoplasms* / genetics
  • Triple Negative Breast Neoplasms* / immunology
  • Triple Negative Breast Neoplasms* / pathology
  • Triple Negative Breast Neoplasms* / therapy
  • V-Set Domain-Containing T-Cell Activation Inhibitor 1* / genetics
  • V-Set Domain-Containing T-Cell Activation Inhibitor 1* / metabolism


  • V-Set Domain-Containing T-Cell Activation Inhibitor 1
  • VTCN1 protein, human
  • Immune Checkpoint Inhibitors
  • Vtcn1 protein, mouse
  • B7-H1 Antigen
  • CD274 protein, human