Prognostic Significance of B7H3 Expression in Solid Tumors: A Systematic Review and Meta-Analysis

B7H3 (CD276), an immunoregulatory molecule known for its role in immune evasion by transmitting inhibitory signals to T lymphocytes, has garnered significant attention in recent years as a promising target for cancer immunotherapy. This interest is largely due to its high expression in various types of solid tumors, coupled with low protein levels in normal tissues. However, studies examining the impact of B7H3 on survival outcomes have shown inconsistent results, leaving its prognostic significance not fully clarified. Therefore, this meta-analysis aimed to assess the relationship between B7H3 expression and various prognostic parameters in patients with solid malignancies. PubMed, Web of Science (WOS), Cochrane, SCOPUS, and Embase databases were searched for eligible articles published until November 2024. Statistical analysis was performed using R studio (version 4.3.2). The analysis included a total of 51 eligible studies comprising 11,135 patients. Results showed that overexpression of B7H3 is a negative predictor for all examined survival outcomes: OS (HR = 1.71, 95% CI = 1.44–2.03, p < 0.0001), DFS (HR = 2.02, 95% CI = 1.49–2.73, p < 0.0001), PFS (HR = 2.10, 95% CI = 1.44–3.06, p < 0.0001), RFS (HR = 1.66, 95% CI = 1.11–2.48, p = 0.01), and DSS (HR = 1.70, 95% CI = 1.24–2.32, p < 0.01). Despite the high heterogeneity observed across the studies, the sensitivity analysis confirmed the robustness of these results. This research suggests that B7H3 may serve as an effective biomarker for prognosis in solid tumors.