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Posterior fossa ependymomas (EPN_PF) in children comprise two morphologically identical, but biologically distinct tumor entities. Group-A (EPN_PFA) tumors have a poor prognosis and require intensive therapy. In contrast, group-B tumors (EPN_PFB) exhibit excellent prognosis and the current consensus opinion recommends future clinical trials to test the possibility of treatment de-escalation in these patients. Therefore, distinguishing these two tumor subtypes is critical. EPN_PFA and EPN_PFB can be distinguished based on DNA methylation signatures, but these assays are not routinely available. We have previously shown that a subset of poorly prognostic childhood EPN_PF exhibits global reduction in H3K27me3. Therefore, we set out to determine whether a simple immunohistochemical assay for H3K27me3 could be used to segregate EPN_PFA from EPN_PFB tumors. We assembled a cohort of 230 childhood ependymomas and H3K27me3 immunohistochemistry was assessed as positive or negative in a blinded manner. H3K27me3 staining results were compared with DNA methylation-based subgroup information available in 112 samples [EPN_PFA (n = 72) and EPN_PFB tumors (n = 40)]. H3K27me3 staining was globally reduced in EPN_PFA tumors and immunohistochemistry showed 99% sensitivity and 100% specificity in segregating EPN_PFA from EPN_PFB tumors. Moreover, H3K27me3 immunostaining was sufficient to delineate patients with worse prognosis in two independent, non-overlapping cohorts (n = 133 and n = 97). In conclusion, immunohistochemical evaluation of H3K27me3 global reduction is an economic, easily available and readily adaptable method for defining high-risk EPN_PFA from low-risk posterior fossa EPN_PFB tumors to inform prognosis and to enable the design of future clinical trials.

Background: The cure rate for childhood intracranial ependymoma is approximately 70% in the setting of a gross total resection followed by radiation, but management remains challenging in patients with residual disease. Therefore, robust biomarkers are needed to guide the development of new targeted therapy. The authors evaluated the expression of several biomarkers in pediatric intracranial ependymoma and observed that the expression of enhancer of zeste homolog 2 (EZH2), a polycomb complex protein involved in epigenetic regulation of gene expression, was independently associated with poor survival., Methods: Tissue microarray immunostaining was performed on 180 ependymoma samples from 12 of 16 Canadian pediatric centers. Expression levels of EZH2, Ki-67, B lymphoma Moloney-murine leukemia virus insertion region 1 homolog, tumor protein 16 (P16), Y-box binding protein 1, phosphorylated protein kinase B (pAKT), and epidermal growth factor receptor were evaluated. Cox regression analyses were performed, and the Kaplan-Meier method was used to construct survival curves., Results: EZH2 expressed in 16% of tumors was associated with inferior 5-year overall survival. Ki-67 and pAKT levels were associated with a poor outcome in patients with posterior fossa ependymoma, and the absence of P16 was associated with a poor outcome in patients with supratentorial ependymoma. Multivariate analysis revealed that younger age and EZH2 expression (95% confidence interval, 1.1-36.0) were independent markers of a poor prognosis., Conclusions: EZH2 is a novel, independent marker of a poor prognosis in patients with ependymoma, especially in those who have tumors located in the posterior fossa. EZH2, pAKT, and P16 are potential therapeutic targets, particularly for patients who have tumors in which standard gross total resection plus fractionated radiotherapy is not feasible., (© 2015 American Cancer Society.)

Purpose: Gross total resection (GTR) of intracranial ependymoma is an accepted goal. More controversial is radiotherapy deferral. This study reports on children treated with gross total resection who did not receive upfront adjuvant radiotherapy., Methods: We conducted a retrospective review of children with intracranial ependymoma in 12 Canadian centers. Patients who had GTR of their tumor and no upfront radiotherapy were identified. Immunostaining was performed for Ki-67, epidermal growth factor receptor (EGFR), and EZH2 on archived tissue. The Kaplan-Meier survival analysis was performed and compared with those who had GTR followed by radiation., Results: Twenty-six children were identified treated with GTR alone at diagnosis; 12 posterior fossa ependymoma (PFE) WHO grade II, and 14 supratentorial ependymoma (STE). Progression-free survival (PFS) in ependymoma treated with GTR alone at diagnosis was inferior in those with high Ki-67 or positive EZH2 immunostaining. Survival was inferior for patients less than 2 years old at diagnosis (p = 0.002). Survival was comparable to PFE WHO grade II and STE who had GTR followed by radiation (p = 0.62). Five-year PFS and overall survival (OS) of those treated with GTR alone were 60 and 70% respectively for PFE and 45 and 70% respectively for STE (p = 0.2; 0.55)., Conclusions: This study suggests that there is a subset of children with certain biologic features who, in the setting of a prospective clinical trial, might be candidates for observation following GTR. Good risk factors for this approach include age of 2 years or older, low Ki-67, and negative EZH2. If relapse occurs, it may be confined to the primary site, allowing for possible salvage with GTR followed by XRT.

The determination of optimal therapy for ependymoma (EP) in infants is ongoing. We describe the incidence, management and outcomes of Canadian infants with EP to discern potential future research questions. Of 579 cases registered in a national database of children <36 months of age diagnosed with a brain tumor from 1990 to 2005, inclusive, 75 (13 %) were EP. These cases were analyzed. A mean annual age-adjusted incidence rate of 4.6 per 100,000 children years was calculated. The male:female ratio was 1.77. Of the tumors, 80 % were infratentorial in location, 67 % were WHO grade II histology, and 29 % were metastatic at diagnosis. All patients underwent a surgical procedure. A complete resection of the tumor was achieved in 56 % of the cases; 43 % of these patients survive while 36 % of the patients with tumors less than completely resected survive. Initial therapy consisted of surgery alone in 23 % of patients, or surgery plus chemotherapy (37 %), radiation therapy (RT; 19 %), or both (21 %). Any use of RT increased with patient age. The 5-year EFS rates for patients in each of the four treatment groups was 22, 11.5, 46.2 and 64.8 %, respectively. For all patients the median survival was 63 ± 6 months and 5-year overall survival was 55 ± 6 %. Patients treated with surgery and chemotherapy alone were younger and had a lower rate of survival than older patients who were more often treated with radiation therapy containing regimens. Further study is needed to determine which patients are optimally served with these treatment modalities.

Background: The randomized controlled Pediatric Oncology Group study 9233 tested the hypothesis that dose-intensive (DI) chemotherapy would improve event-free survival (EFS) for children <3 years of age with newly diagnosed malignant brain tumors., Methods: Of 328 enrolled eligible patients, diagnoses were medulloblastoma (n = 112), ependymoma (n = 82), supratentorial primitive neuroectodermal tumor (sPNET, n = 38) and other malignant brain tumors (n = 96), and were randomized to 72 weeks of standard dose chemotherapy (Regimen A, n = 162) or DI chemotherapy (Regimen B, n = 166). Radiation therapy (RT) was recommended for patients with evidence of disease at completion of chemotherapy or who relapsed within 6 months of chemotherapy completion., Results: Distributions of EFS for Regimens A and B were not significantly different (P = 0.32) with 2- and 10-year rates of 22.8% ± 3.3% and 15.4% ± 3.7%, and 27.1% ± 3.4% and 20.8% ± 3.8%, respectively. Thus, the study hypothesis was rejected. While distributions of EFS and OS were not significantly different between Regimens A and B for patients with medulloblastoma and sPNET, DI chemotherapy resulted in significantly improved EFS distribution (P = .0011) (2-year EFS rates of 42.1% vs. 19.6% with SD chemotherapy), but not OS distribution, for patients with centrally confirmed ependymoma. The degree of surgical resection affected EFS, OS or both for most tumor groups. Approximately 20%, 40% and 20% of patients with medulloblastoma, ependymoma treated with DI chemotherapy, and sPNET, respectively appear to have been cured without RT. Of 11 toxic deaths on study, 10 occurred on the DI chemotherapy arm., Conclusions: Prolonged dose-intensive chemotherapy given to infants with malignant brain tumors resulted in increased EFS only for patients with ependymoma.

Primary CNS tumors are the leading cause of cancer-related death in pediatrics. It is essential to understand treatment trends to interpret national survival data. In Canada, children with CNS tumors are treated at one of 16 tertiary care centers. We surveyed pediatric neuro-oncologists to create a national standard of practice to be used in the absence of a clinical trial for seven of the most prevalent brain tumors in children. This allowed description of practice across the country, along with a consensus. This had a multitude of benefits, including understanding practice patterns, allowing for a basis to compare in future research and informing Health Canada of the current management of patients. This also allows all children in Canada to receive equivalent care, regardless of location. [ABSTRACT FROM AUTHOR]