B7-H3 (CD276) and CD47 Expression Are Associated with Immune Evasion and Survival Outcomes in Pediatric...

Background: Medulloblastoma is the most common malignant pediatric central nervous system tumor and exhibits marked molecular and clinical heterogeneity. Immune evasion pathways may contribute to tumor aggressiveness and represent potential prognostic and therapeutic targets. We investigated the clinicopathological and prognostic relevance of the immune checkpoint molecules B7-H3 (CD276) and CD47 in medulloblastoma. Methods: We screened 77 patients treated between April 2015 and December 2025; in total, 32 patients with pathologically confirmed medulloblastoma and complete data were included. Tumor B7-H3 and CD47 expression was assessed using immunohistochemistry and an immunoreactivity score (IRS); patients were categorized as having negative/low (IRS < 4) or high (IRS ≥ 4) expression. We analyzed the associations with clinicopathological and molecular features. Overall survival (OS) and disease-free survival (DFS) were evaluated using Kaplan-Meier and log-rank tests. Prognostic factors were examined using univariate and multivariate Cox regression. Results: High B7-H3 expression was associated with shorter OS (median 46 vs. 85 months; p = 0.024) and markedly reduced DFS (median 21 vs. 102 months; p < 0.001). High CD47 expression was also associated with shorter OS (median 56 vs. 102 months; p = 0.025), whereas DFS did not significantly differ by CD47 status (p = 0.200). B7-H3 and CD47 expression levels were not correlated (Spearman's rho = 0.071; p = 0.699). In the univariate analysis, high B7-H3 expression predicted mortality (HR = 25.79; p = 0.002) and recurrence risk (HR = 136.23; p = 0.045), and high CD47 expression predicted mortality (HR = 4.82; p = 0.042). In the multivariate analysis, high B7-H3 expression remained an independent predictor of poor OS (HR = 31.01; p = 0.004), whereas radiotherapy independently reduced the recurrence risk (HR = 0.197; p = 0.024). Conclusions: B7-H3 is a strong independent adverse prognostic biomarker for OS and is associated with profoundly shorter DFS in medulloblastoma, supporting its relevance as a candidate target for immune-directed strategies.