Transcriptomic analysis reveals differential regulation of synaptic components in pediatric and adult brain tumors.

UNLABELLED: Neuronal-cancer cell interactions are a key component of brain tumor pathophysiology, yet many fundamental questions remain unanswered - with even more remaining unasked. Here, we present a comprehensive brain tumor reference map generated from bulk RNA-seq data of ∼4,300 adult and pediatric brain tumors-including various glioma subtypes, medulloblastomas, ependymomas, and meningiomas-alongside ∼1,400 healthy brain samples. By analyzing synaptic processes and synaptic gene expression across tumor types, we reveal the complexity of neuron-tumor crosstalk and its potential impact on patient survival. Our findings identify key synaptic signaling pathways and dysregulated patterns in brain tumors, including HNRNPH2 upregulation, a key factor in RNA processing and metabolism, in gliomas and medulloblastomas. Additionally, we highlight the role of cholinergic signaling, particularly CHRNA9 , as a driver of glioma progression, which is also upregulated in WNT and Group 4 medulloblastomas, ependymomas, and meningiomas. Furthermore, P2 purinergic signaling emerges as a key player in glioma progression. These insights lay the groundwork for future studies exploring whether targeting these pathways could reprogram the tumor microenvironment toward an anti-tumor state, ultimately leading to novel therapeutic strategies and improved patient outcomes.

HIGHLIGHTS: A comprehensive brain tumor reference map was generated using bulk RNA-seq from ∼4,300 adult and pediatric brain tumors and ∼1,400 healthy brain samples. HNRNPH2 is consistently upregulated across all adult and pediatric gliomas, as well as all medulloblastoma subgroups. Nicotinic acetylcholine receptors (nAChRs) are upregulated in glioblastomas and pediatric high-grade gliomas but downregulated in low-grade gliomas, underscoring their role in glioma aggressiveness. CHRNA9 is a key driver of glioma progression and is also upregulated in medulloblastomas (WNT and Group 4), ependymomas, and meningiomas.