BDNF and central nervous system cancer: Mature BDNF expression is significantly increased in high‐grade glioma tissues compared to low‐grade gliomas and control tissues. Similarly, TrkB expression is markedly elevated in high‐grade gliomas. A positive association was found between mature BDNF and TrkB expression levels with the malignancy grade of glioma, indicating a potential role in glioma progression.