Grade II and III gliomas are generally slowly progressing brain cancers, many of which eventually transform into more aggressive tumors. Despite recent findings of frequent mutations in IDH1 and other genes, knowledge about their pathogenesis is still incomplete. Here, combining two large sets of high-throughput sequencing data, we delineate the entire picture of genetic alterations and affected pathways in these glioma types, with sensitive detection of driver genes. Grade II and III gliomas comprise three distinct subtypes characterized by discrete sets of mutations and distinct clinical behaviors. Mutations showed significant positive and negative correlations and a chronological hierarchy, as inferred from different allelic burdens among coexisting mutations, suggesting that there is functional interplay between the mutations that drive clonal selection. Extensive serial and multi-regional sampling analyses further supported this finding and also identified a high degree of temporal and spatial heterogeneity generated during tumor expansion and relapse, which is likely shaped by the complex but ordered processes of multiple clonal selection and evolutionary events.

Subtype-specific genetic lesions can be used to stratify patients within each LGG subtype. enabling better prognostication and management.

BACKGROUND Addition of temozolomide (TMZ) to radiotherapy (RT) improves overall survival (OS) in glioblastoma, but previous studies suggest that patients with tumors harboring an unmethylated MGMT promoter derive minimal benefit. The aim of this open-label, phase 3 CheckMate 498 study was to evaluate the efficacy of nivolumab (NIVO)+RT compared with TMZ+RT in newly diagnosed glioblastoma with unmethylated MGMT promoter. METHODS Patients were randomized 1:1 to standard RT (60 Gy) + NIVO (240 mg every 2 weeks for 8 cycles, then 480 mg every 4 weeks) or RT+TMZ (75 mg/m 2 daily during RT and 150-200 mg/m 2/day 5/28 days during maintenance). The primary endpoint was OS. RESULTS A total of 560 patients were randomized, 280 to each arm. Median OS was 13.4 months (95% CI, 12.6-14.3) with NIVO+RT and 14.9 months (95% CI, 13.3-16.1) with TMZ+RT (hazard ratio [HR], 1.31; 95% CI, 1.09-1.58; P=0.0037). Median progression-free survival was 6.0 months (95% CI, 5.7-6.2) with NIVO+RT and 6.2 months (95% CI, 5.9-6.7) with TMZ+RT (HR, 1.38; 95% CI, 1.15-1.65). Response rates were 7.8% (9/116) with NIVO+RT and 7.2% (8/111) with TMZ+RT; grade 3/4 treatment-related adverse event (TRAE) rates were 21.9% and 25.1%, and any-grade serious TRAE rates were 17.3% and 7.6%, respectively. CONCLUSIONS The study did not meet the primary endpoint of improved OS; TMZ+RT demonstrated a longer median OS than NIVO+RT. No new safety signals were detected with NIVO in this study. The difference between the study treatment arms is consistent with the use of TMZ+RT as standard of care for glioblastoma.

BACKGROUND AND PURPOSE:Positron-emission tomography (PET) is a useful tool in oncology. The aim of this study was to assess the metabolic activity of gliomas using 11 C-methionine (MET), [ 18 F] fluorodeoxyglucose (FDG), and 11 C-choline (CHO) PET and to explore the correlation between the metabolic activity and histopathologic features.

The NCI Common Terminology Criteria for Adverse Events v3.0 is a descriptive terminology which can be utilized for Adverse Event (AE) reporting. A grading (severity) scale is provided for each AE term.