Adriana Olar

TERT Promoter Mutations and Risk of Recurrence in Meningioma

The World Health Organization (WHO) classification and grading system attempts to predict the clinical course of meningiomas based on morphological parameters. However, because of high interobserver variation of some criteria, more reliable prognostic markers are required. Here, we assessed the TERT promoter for mutations in the hotspot regions C228T and C250T in meningioma samples from 252 patients. Mutations were detected in 16 samples (6.4% across the cohort, 1.7%, 5.7%, and 20.0% of WHO grade I, II, and III cases, respectively). Data were analyzed by t test, Fishers exact test, log-rank test, and Cox proportional hazard model. All statistical tests were two-sided. Within a mean follow-up time in surviving patients of 68.1 months, TERT promoter mutations were statistically significantly associated with shorter time to progression (P < .001). Median time to progression among mutant cases was 10.1 months compared with 179.0 months among wild-type cases. Our results indicate that the inclusion of molecular data (ie, analysis of TERT promoter status) into a histologically and genetically integrated classification and grading system for meningiomas increases prognostic power. Consequently, we propose to incorporate the assessment of TERT promoter status in upcoming grading schemes for meningioma.

Lambrolizumab induced central nervous system (CNS) toxicity

Programmed death 1(PD-1) is a strategic receptor on activated T-cells that mediates immunosuppression in cancer. Lambrolizumab is a humanized monoclonal IgG4–kappa isotype antibody designed to block the negative immune regulatory signaling of the PD-1 receptor expressed by T cells.1 Anti–PD-1 monoclonal antibodies have activity against several solid tumors.2 Recently, the FDA designated lambrolizumab as a breakthrough therapy for patients with advanced melanoma. We describe a patient with metastatic melanoma placed on a clinical trial with lambrolizumab who developed CNS toxicity.

Mitotic Index is an Independent Predictor of Recurrence‐Free Survival in Meningioma

While World Health Organization (WHO) grading of meningioma stratifies patients according to recurrence risk overall, there is substantial within‐grade heterogeneity with respect to recurrence‐free survival (RFS). Most meningiomas are graded according to mitotic counts per unit area on hematoxylin and eosin sections, a method potentially confounded by tumor cellularity, as well as potential limitations of accurate mitotic figure detection on routine histology. To refine mitotic figure assessment, we evaluated 363 meningiomas with phospho‐histone H3 (Ser10) and determined the mitotic index (number of mitoses per 1000 tumor cells). The median mitotic indices among WHO grade I (n = 268), grade II (n = 84) and grade III (n = 11) tumors were 1, 4 and 12. Classification and regression tree analysis to categorize cut‐offs identified three subgroups defined by mitotic indices of 0–2, 3–4 and ≥5, which on univariate analysis were associated with RFS (P < 0.01). In multivariate analysis, mitotic index subgrouped in this manner was significantly associated with RFS (P < 0.01) after adjustment for Simpson grade, WHO grade and MIB‐1 index. Mitotic index was then examined within individual WHO grade, showing that for grade I and grade II meningiomas, mitotic index can add additional information to RFS risk. The results suggest that the use of a robust mitotic marker in meningioma could refine risk stratification.

Absence of IDH1-R132H mutation predicts rapid progression of nonenhancing diffuse glioma in older adults

Advanced age and contrast enhancement portend a poor prognosis in diffuse glioma (DG). Diffuse glioma may present as nonenhancing tumors that rapidly progress in weeks to months to a pattern of ring enhancement, characteristic of glioblastoma (GBM). Mutations involving isocitrate dehydrogenase 1 (IDH1) have recently emerged as important diagnostic and prognostic markers in DG. R132H is the most common mutation, expressed in more than 80% of DG and secondary GBM but in less than 10% of primary GBM. Adults older than 50 years with nonenhancing, rapidly progressing DG were identified. A comparison group comprised randomly selected, age-matched patients with nonenhancing, nonprogressing DG. Isocitrate dehydrogenase 1 status was evaluated using anti-IDH1-R132H antibodies (Dianova, Hamburg, Germany). The results were correlated with the clinical outcomes. We identified 4 patients who presented with nonenhancing DG that rapidly progressed to ring-enhancing lesions that were subsequently diagnosed on surgical resection as GBM. This group showed absent IDH1-R132H expression, which is characteristic of primary GBM. The comparison group of 5 patients presented with nonenhancing, nonprogressing DG, and all 5 tumors showed IDH1-R132H expression. In conclusion, negative IDH1-R132H mutation status in nonenhancing DG of older adults is a poor prognostic factor associated with rapid progression to ring-enhancing GBM. The shorter interval of progression and negative IDH1-R132H mutation status suggest a similar molecular pathway as seen in primary GBM.

Molecular Markers in Low Grade Glioma – Toward Tumor Reclassification

Low-grade diffuse gliomas are a heterogeneous group of primary glial brain tumors with highly variable survival. Currently, patients with low-grade diffuse gliomas are stratified into risk subgroups by subjective histopathologic criteria with significant interobserver variability. Several key molecular signatures have emerged as diagnostic, prognostic, and predictor biomarkers for tumor classification and patient risk stratification. In this review, we discuss the effect of the most critical molecular alterations described in diffuse (IDH1/2, 1p/19q codeletion, ATRX, TERT, CIC, and FUBP1) and circumscribed (BRAF-KIAA1549, BRAF(V600E), and C11orf95-RELA fusion) gliomas. These molecular features reflect tumor heterogeneity and have specific associations with patient outcome that determine appropriate patient management. This has led to an important, fundamental shift toward developing a molecular classification of World Health Organization grade II-III diffuse glioma.

Methylation profiling of choroid plexus tumors reveals 3 clinically distinct subgroups

BACKGROUND Choroid plexus tumors are intraventricular neoplasms derived from the choroid plexus epithelium. A better knowledge of molecular factors involved in choroid plexus tumor biology may aid in identifying patients at risk for recurrence. METHODS Methylation profiles were examined in 29 choroid plexus papillomas (CPPs, WHO grade I), 32 atypical choroid plexus papillomas (aCPPs, WHO grade II), and 31 choroid plexus carcinomas (CPCs, WHO grade III) by Illumina Infinium HumanMethylation450 Bead Chip Array. RESULTS Unsupervised hierarchical clustering identified 3 subgroups: methylation cluster 1 (pediatric CPP and aCPP of mainly supratentorial location), methylation cluster 2 (adult CPP and aCPP of mainly infratentorial location), and methylation cluster 3 (pediatric CPP, aCPP, and CPC of supratentorial location). In methylation cluster 3, progression-free survival (PFS) accounted for a mean of 72 months (CI, 55-89 mo), whereas only 1 of 42 tumors of methylation clusters 1 and 2 progressed (P< .001). On stratification of outcome data according to WHO grade, all CPCs clustered within cluster 3 and were associated with shorter overall survival (mean, 105 mo [CI, 81-128 mo]) and PFS (mean, 55 mo [CI, 36-73 mo]). The aCPP of methylation cluster 3 also progressed frequently (mean, 69 mo [CI, 44-93 mo]), whereas no tumor progression was observed in aCPP of methylation clusters 1 and 2 (P< .05). Only 1 of 29 CPPs recurred. CONCLUSIONS Methylation profiling of choroid plexus tumors reveals 3 distinct subgroups (ie, pediatric low-risk choroid plexus tumors [cluster 1], adult low-risk choroid plexus tumors [cluster 2], and pediatric high-risk choroid plexus tumors [cluster 3]) and may provide useful prognostic information in addition to histopathology.

Clinical and prognostic features of adult patients with gangliogliomas

BACKGROUND Gangliogliomas (GGs) represent <1% of primary brain tumors in adults. Little is known regarding prognostic features, clinical characteristics, or the impact of treatment on patient outcomes. METHODS Our neuro-oncology longitudinal database was screened for patients with GG from 1992 to 2012. Sixty-seven patients (age >18 y) were identified. RESULTS Sixty-two patients presented with low-grade GG and 5 with anaplastic GG. The median age at diagnosis was 29 years. With a median follow-up of 4.7 years after the initial diagnosis, 23 patients had progressive disease. Range of time to progression was 0.2-20 years. Nine patients with low-grade GG progressed to a malignant tumor. The median overall survival (OS) for all patients was not reached. The 2-, 5-, and 10-year OS for patients with low-grade GG were 100%, 88% (95% confidence interval [CI]: 73%, 95%), and 84% (95% CI: 67%, 93%), respectively. Factors identified by univariate analysis that were significantly associated with OS were age, KPS, extent of resection (EOR), and grade. Factors on univariate analysis that were significantly associated with progression-free survival were grade and EOR. On multicovariate Cox regression, lower tumor grade and younger age were significant factors for longer OS. EOR is a significant factor for progression-free survival. CONCLUSIONS While GG has excellent prognosis, malignant histologic grade, older age, and diagnosis with biopsy could indicate worse prognosis. The late nature and high rate of progression emphasize the importance of long-term follow-up. The role of chemotherapy and radiation therapy for incompletely resected low-grade GG remains unclear.

Isocitrate dehydrogenase 1 R132H mutation is not detected in angiocentric glioma

Mutations of isocitrate dehydrogenase-1 gene (IDH1), most commonly resulting in replacement of arginine at position 132 by histidine (R132H), have been described in World Health Organization grade II and III diffuse gliomas and secondary glioblastoma. Immunohistochemistry using a mouse monoclonal antibody has a high specificity and sensitivity for detecting IDH1 R132H mutant protein in sections from formalin-fixed, paraffin-embedded tissue. Angiocentric glioma (AG), a unique neoplasm with mixed phenotypic features of diffuse glioma and ependymoma, has recently been codified as a grade I neoplasm in the 2007 World Health Organization classification of central nervous system tumors. The present study was designed to evaluate IDH1 R132H protein in AG. Three cases of AG were collected, and the diagnoses were confirmed. Expression of mutant IDH1 R132H protein was determined by immunohistochemistry on representative formalin-fixed, paraffin-embedded sections using the antihuman mouse monoclonal antibody IDH1 R132H (Dianova, Hamburg, Germany). Known IDH1 mutation-positive and IDH1 wild-type cases of grade II to IV glioma served as positive and negative controls. All 3 patients were male, aged 3, 5, and 15 years, with intra-axial tumors in the right posterior parietal-occipital lobe, right frontal lobe, and left frontal lobe, respectively. All 3 cases showed characteristic morphologic features of AG, including a monomorphous population of slender bipolar cells that diffusely infiltrated cortical parenchyma and ensheathed cortical blood vessels radially and longitudinally. All 3 cases were negative for the presence of IDH1 R132H mutant protein (0/3). All control cases showed appropriate reactivity. IDH1 R132H mutation has been described as a common molecular signature of grade II and III diffuse gliomas and secondary glioblastoma; however, AG, which exhibits some features of diffuse glioma, has not been evaluated. The absence of mutant IDH1 R132H protein expression in AG may help further distinguish this unique neoplasm from diffuse glioma.

C11orf95–RELA fusion present in a primary supratentorial ependymoma and recurrent sarcoma

Ependymomas are rare glial tumors of the central nervous system that arise from the cells lining the ventricles and central canal within the spinal cord. The distribution of these tumors along the neuroaxis varies by age, most commonly involving the spinal cord in adults and the posterior fossa in children. It is becoming evident that ependymomas of infratentorial, supratentorial, and spinal cord location are genetically distinct which may explain the differences in clinical outcomes. A novel oncogenic fusion involving the C11orf95 and RELA genes was recently described in supratentorial ependymomas that results in constitutive aberrant activation of the nuclear factor-kB signaling pathway. Ependymosarcomas are rare neoplasms in which a malignant mesenchymal component arises within an ependymoma. We here describe a case of a sarcoma developing in a patient previously treated with chemotherapy and radiation whose original ependymoma and recurrent sarcoma were both shown to carry the type 1 C11orf95–RELA fusion transcript indicating a monoclonal origin for both tumors.

Identification of histological correlates of overall survival in lower grade gliomas using a bag-of-words paradigm: A preliminary analysis based on hematoxylin & eosin stained slides from the lower grade glioma cohort of the cancer genome Atlas

Background: Glioma, the most common primary brain neoplasm, describes a heterogeneous tumor of multiple histologic subtypes and cellular origins. At clinical presentation, gliomas are graded according to the World Health Organization guidelines (WHO), which reflect the malignant characteristics of the tumor based on histopathological and molecular features. Lower grade diffuse gliomas (LGGs) (WHO Grade II–III) have fewer malignant characteristics than high-grade gliomas (WHO Grade IV), and a better clinical prognosis, however, accurate discrimination of overall survival (OS) remains a challenge. In this study, we aimed to identify tissue-derived image features using a machine learning approach to predict OS in a mixed histology and grade cohort of lower grade glioma patients. To achieve this aim, we used H and E stained slides from the public LGG cohort of The Cancer Genome Atlas (TCGA) to create a machine learned dictionary of “image-derived visual words” associated with OS. We then evaluated the combined efficacy of using these visual words in predicting short versus long OS by training a generalized machine learning model. Finally, we mapped these predictive visual words back to molecular signaling cascades to infer potential drivers of the machine learned survival-associated phenotypes. Methods: We analyzed digitized histological sections downloaded from the LGG cohort of TCGA using a bag-of-words approach. This method identified a diverse set of histological patterns that were further correlated with OS, histology, and molecular signaling activity using Cox regression, analysis of variance, and Spearman correlation, respectively. A support vector machine (SVM) model was constructed to discriminate patients into short and long OS groups dichotomized at 24-month. Results: This method identified disease-relevant phenotypes associated with OS, some of which are correlated with disease-associated molecular pathways. From these image-derived phenotypes, a generalized SVM model which could discriminate 24-month OS (area under the curve, 0.76) was obtained. Conclusion: Here, we demonstrated one potential strategy to incorporate image features derived from H and E stained slides into predictive models of OS. In addition, we showed how these image-derived phenotypic characteristics correlate with molecular signaling activity underlying the etiology or behavior of LGG.