TGFB1 and central nervous system cancer: In the KEGG enrichment analysis, while the upregulated genes of glioma grades were enriched in p53, TGF-β, and Notch signaling pathways, prominent downregulated gene clusters fell into synaptic function related pathways, such as glutamatergic, GABAergic, serotonergic, and dopaminergic pathways (Figure 3B, Supplementary Table S3).