Genomic evolution of low and high grade glioma

Malignant transformation (MT) of IDH-mutant low-grade glioma (LGG) to aggressive high grade tumors is an event of major clinical significance, eventually leading to death in the majority of LGG patients. While patients with primary glioblastoma (GBM) have benefited from increased overall survival due to treatment with the alkylating chemotherapy temozolomide (TMZ), the benefit of TMZ for patients with diffuse low-grade gliomas (LGG) remains unknown. To further explore the relationships among TMZ treatment, hypermutation and malignant progression, we studied tumor evolution in an expanded cohort of untreated and TMZ-treated patients by exome-sequencing of paired IDH1/IDH2-mutant LGGs and their post-TMZ recurrences. Together, these findings further our understanding of the molecular features and clinical behavior of hypermutated clones. The heterogeneity present in individual tumors, i.e. intratumoral heterogeneity (ITH), is thought to be a major reason why... (for more see dbGaP study page.)