PROJECT SUMMARY / ABSTRACT Meningiomas are the most common primary brain tumors. While typically of benign histology, they can be associated with significant neurological morbidity and have the potential for malignant transformation. In our previous studies, we completed genomic analysis of over 700 meningiomas using whole exome and targeted next-generation sequencing, identifying driver mutations in 12 genes and establishing mutually exclusive molecular subgroups. We now propose to investigate the molecular mechanisms underlying the formation of TRAF7-dependent meningiomas (which represent up to one quarter of all meningiomas), undertake molecular genomic analyses to identify somatic coding and non-coding or genomic events in TRAF7 tumors that progress to higher grades. We also propose to test and validate candidate drug efficacy using primary cultures from surgically resected meningiomas carrying TRAF7 aberrations, as well as mouse models of meningioma that we have established.