B7-H3

B7-H3

Summary

B7-H3 (CD276) is a tumor-associated immune-related protein that functions as a tumor-selective binding target and mediator of cis-inhibition. It is markedly upregulated across EGFR-positive malignancies while showing minimal expression in healthy tissues, supporting its use in selective cancer targeting. In a reported bispecific antibody strategy, ibi334 leverages B7-H3-mediated cis-inhibition of EGFR to enhance anti-tumor efficacy and reduce toxicities (PMID:41735305). B7-H3 expression was also significantly elevated in the immune-resistant colorectal cancer organoid fraction, linking it to therapy resistance (PMID:41920069). Beyond cell-surface targeting, B7-H3 is enriched in exosomes and influences exosome biogenesis, signaling, and tumor progression, with implications for immune evasion and metastasis (PMID:41964005). These properties have made antibody drug conjugates and bispecific T cell engagers targeting B7-H3 attractive next-generation approaches in pediatric solid tumors (PMID:41984108).

Key Findings

EGFR-positive malignancies and bispecific targeting

  • B7-H3 is markedly upregulated across EGFR-positive malignancies with minimal expression in healthy tissues, supporting tumor-selective targeting (PMID:41735305).
  • ibi334 is an EGFR/B7-H3 bispecific antibody designed to exploit B7-H3-mediated cis-inhibition for enhanced anti-tumor efficacy and lower toxicity (PMID:41735305).
  • The reported mechanism centers on cis-inhibition of EGFR by B7-H3, highlighting a functional role beyond simple antigen display (PMID:41735305).

Colorectal cancer and immune resistance

  • Immune-resistant colorectal cancer organoid fractions showed significantly elevated B7-H3 expression, associating it with resistant tumor states (PMID:41920069).
  • B7-H3-enriched exosomes are proposed as diagnostic, prognostic, and predictive biomarkers in colorectal cancer (PMID:41964005).
  • The same exosome-associated signature is also highlighted for biomarker potential in non-small cell lung cancer and prostate cancer (PMID:41964005).

Exosomes and tumor microenvironment

  • B7-H3 is enriched in exosomes and influences exosome biogenesis, signaling, and tumor progression (PMID:41964005).
  • B7-H3-enriched exosomes modulate the tumor microenvironment to promote immune evasion, metastasis, and therapy resistance (PMID:41964005).
  • This positions B7-H3 as a nexus between vesicle biology and cancer progression rather than only a surface antigen (PMID:41964005).

Pediatric solid tumors and therapeutic targeting

  • B7-H3 is a tumor-associated antigen targeted by next-generation antibody drug conjugates in pediatric solid tumors (PMID:41984108).
  • Bispecific T cell engagers targeting B7-H3 are also being explored in multimodal immunotherapy strategies for pediatric solid tumors (PMID:41984108).
  • The literature frames B7-H3 as a rational target for overcoming biological barriers in pediatric cancer immunotherapy (PMID:41984108).