Brain-Derived Neurotrophic Factor (BDNF) as a Potential Biomarker in Brain Glioma: A Systematic Review and Meta-Analysis

Background: This systematic review and meta-analysis evaluates peripheral and CNS BDNF levels in glioma patients. Methods: Following PRISMA guidelines, we systematically searched databases for studies measuring BDNF in glioma patients and controls. After screening and data extraction, we conducted quality assessment, meta-analysis, and meta-regression. Results: Eight studies were included. Meta-analysis showed significantly reduced plasma BDNF levels in glioma patients versus controls (SMD: −1.0026; 95% CI: [−1.5284, −0.4769], p = 0.0002). High-grade gliomas had lower plasma BDNF (p = 0.0288). Tissue BDNF levels were higher in glioma patients (SMD: 1.9513; 95% CI: [0.7365, 3.1661], p = 0.0016) and correlated with tumor grade (p = 0.0122). Plasma BDNF levels negatively correlated with patient age (p = 0.0244) and positively with female percentage (p = 0.0007). Conclusion: BDNF is a promising biomarker in glioma, showing significant changes in plasma and tissue levels correlating with tumor grade, patient age, and gender.