Glioblastoma is both the most common and lethal primary malignant brain tumor. Extensive multiplatform genomic characterization has provided a higher-resolution picture of the molecular alterations underlying this disease. These studies provide the emerging view that “glioblastoma” represents several histologically similar yet molecularly heterogeneous diseases, which influences taxonomic classification systems, prognosis, and therapeutic decisions.

BACKGROUND:The prognosis for patients with atypical and malignant meningioma is guarded; whether the extent of resection is associated with survival-based outcomes in this population remains poorly defined. This study investigated the association between gross total resection (GTR) and all-cause mortality in patients with atypical and malignant meningioma. METHODS: The Surveillance, Epidemiology, and End Results program was used to identify 575 and 64 patients betweens the ages of 18 and 70 years who were diagnosed with atypical and malignant meningioma, respectively, between 2004 and 2009. Multivariate Cox proportional hazards regression was used to assess the adjusted impact of GTR versus subtotal resection on all-cause mortality. RESULTS: Baseline patient characteristics were similar for patients who did undergo GTR and patients who did not undergo GTR. The 5-year overall survival rates were 91.3% (95% confidence interval [CI], 86.2%-94.5%) and 78.2% (95% CI, 70.0%-84.3%) for patients with atypical meningioma who did and did not undergo GTR, respectively, and 64.5% (95% CI, 45.9%-78.1%) and 41.1% (95% CI, 17.9%-63.1%) for patients with malignant meningioma who did and did not undergo GTR, respectively. After adjustments for available, pertinent confounding variables, GTR was associated with lower all-cause mortality in patients with atypical (hazard ratio, 0.39; 95% CI, 0.23-0.67; P <.001) and malignant meningioma (hazard ratio, 0.35; 95% CI, 0.15-0.81; P 5.01). CONCLUSIONS: The extent of resection is a powerful predictor of outcome for patients with atypical and malignant meningioma. These data highlight the hazard associated with the presence of gross tumor bulk after surgery and suggest a value for more extensive resections that should be balanced against the additional potential morbidity. Cancer 2015;121:4376-81.

Here we report that promoter mutations in telomerase (TERT), the most common noncoding mutations in cancer, give rise to monoallelic expression of TERT. Through deep RNA sequencing, we find that TERT activation in human cancer cell lines can occur in either mono- or biallelic manner. Without exception, hotspot TERT promoter mutations lead to the re-expression of only one allele, accounting for approximately half of the observed cases of monoallelic TERT expression. Furthermore, we show that monoallelic TERT expression is highly prevalent in certain tumor types and widespread across a broad spectrum of cancers. Taken together, these observations provide insights into the mechanisms of TERT activation and the ramifications of noncoding mutations in cancer.