B7-H3, also known as CD276, is a tumor-associated immune checkpoint protein with marked upregulation across EGFR-positive malignancies and minimal expression in healthy tissues, making it a tumor-selective binding target. It can mediate cis-inhibition in the context of the EGFR/B7-H3 bispecific antibody ibi334, which enhances anti-tumor efficacy while minimizing toxicities. Functionally, B7-H3 is linked to pro-tumor signaling through activation of pi3k and stat3 pathways, and it also appears in exosomes that influence biogenesis, signaling, and tumor progression. Clinically, it is being explored in colorectal cancer, non-small-cell lung cancer, prostate cancer, and pediatric solid tumors, including as a diagnostic/prognostic biomarker and as a target for antibody-drug conjugates. Recent literature highlights its elevated expression in immune-resistant colorectal cancer organoid fractions and its role in exosome-mediated immune evasion, metastasis, and therapy resistance. Overall, B7-H3 is emerging as a multifunctional therapeutic and biomarker target in oncology, especially where immune resistance and tumor-selective targeting are priorities.
Cancer and tumor-selective targeting
- A 2026 Nature Communications study showed that B7-H3-mediated cis-inhibition of EGFR by the bispecific antibody ibi334 improved anti-tumor efficacy and reduced toxicity in EGFR-positive malignancies. (PMID:41735305)
- B7-H3 is described as a tumor-selective binding target with minimal expression in healthy tissues, supporting its use in selective cancer targeting strategies. (PMID:41735305)
- Next-generation antibody-drug conjugates target B7-H3, and it is also being pursued in bispecific T cell engager approaches for pediatric solid tumors. (PMID:41984108)
- B7-H3 is a tumor-associated antigen highlighted in multimodal immunotherapy strategies for pediatric solid tumors. (PMID:41984108)
Colorectal cancer and immune resistance
- B7-H3 expression was significantly elevated in the immune-resistant colorectal cancer organoid fraction, linking it to resistance-associated tumor states. (PMID:41920069)
- B7-H3-enriched exosomes are proposed as diagnostic, prognostic, and predictive biomarkers in colorectal cancer. (PMID:41964005)
- The colorectal cancer association is reinforced by the reported enrichment of B7-H3 in immune-resistant organoid models. (PMID:41920069)
- Exosome-associated B7-H3 may contribute to colorectal cancer progression through tumor microenvironment modulation. (PMID:41964005)
Exosomes and tumor microenvironment
- A 2026 Cell Communication and Signaling review described B7-H3 as enriched in exosomes and implicated in 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)
- Exosomal B7-H3 has been proposed as a biomarker platform across colorectal cancer, non-small-cell lung cancer, and prostate cancer. (PMID:41964005)
- The exosome-centered literature positions B7-H3 as a therapeutic nexus connecting intercellular communication and immune escape. (PMID:41964005)