BMC Cancer (Oct 2024)

B7-H3 is widely expressed in soft tissue sarcomas

  • Meghan M. Lynch,
  • Rusul Al-Marayaty,
  • Farres Obeidin,
  • Borislav A. Alexiev,
  • Eleanor Y. Chen,
  • Pedro Viveiros,
  • Brett A. Schroeder,
  • Kelly Hudkins,
  • Timothy M. Fan,
  • Mary W. Redman,
  • Kelsey K. Baker,
  • George Jour,
  • Lee D. Cranmer,
  • Seth M. Pollack

DOI
https://doi.org/10.1186/s12885-024-13061-4
Journal volume & issue
Vol. 24, no. 1
pp. 1 – 7

Abstract

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Abstract Purpose Targeted therapy development in soft tissue sarcoma (STS) has been burdened by the heterogeneity of this group of rare tumors. B7 homolog 3 protein (B7-H3) is a molecule in the same family as programmed death-ligand 1 (PD-L1). It has limited expression in noncancerous tissues and is overexpressed in many cancers, making it an attractive target for cancer therapy, and clinical trials targeting B7-H3 are actively underway. While available data demonstrate high expression levels of B7-H3 in individual sarcoma subtypes, its expression patterns across STS subtypes are not well described. The purpose of this study was to characterize the expression patterns of B7-H3 in STS. Patients and methods This retrospective analysis evaluated STS tumor specimens from patients with a variety of different subtypes. Specimens were evaluated by immunohistochemistry (IHC) for expression and staining pattern of B7-H3 both in tumors and in associated vasculature. Results Specimens from 153 sarcoma patients included 15 different STS subtypes. B7-H3 was broadly expressed in 97% of samples (95% CI 0.93–0.99) and 69.2% demonstrated high levels of B7-H3 expression (95% CI 0.61–0.76). No significant association between B7-H3 positivity or expression level and prior treatment(s), tumor size, tumor grade, or patient age. B7-H3 positivity in vessels was found in 94.7% (145/153) of samples. In tumors that had been previously assessed for PD-L1 and PD-1, there was no correlation between B7-H3 positivity or expression and the positivity or expression level of PD-L1 or PD-1. Conclusion These data show high levels of B7-H3 positivity across soft tissue sarcoma subtypes, suggesting its feasibility as a therapeutic target for future sarcoma treatments. Future clinical trials are needed to evaluate whether targeting B7-H3 can provide clinical benefit to help patients with sarcoma.

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