Ependymoma in children: molecular considerations and therapeutic insights

Clinical profile, treatment and outcome of pediatric brain tumors in Serbia in a 10-year period: A national referral institution experience

Objective

This study aimed to evaluate the characteristics of children with primary brain tumors, the effectiveness of treatment modalities, and to detect factors related to the outcome.

Methods

A detailed analysis was performed on a series of 173 pediatric patients treated in a Serbian referral oncology institution between 2007 and 2016, based on their clinical, histological, treatment, and follow-up data.

Results

Mean survival time of all children was 94.5months. 2-, 5- and 10-year overall survival probabilities were 68.8%, 59.4%, and 52.8%, respectively. Patients with supratentorial tumors had longer survival than patients with infratentorial tumors and patients with tumors in both compartments (p = 0.011). Children with the unknown histopathology (brainstem glioma) and high-grade glioma had a shorter life than embryonal tumors, ependymoma, and low-grade glioma (p<0.001). Survival of the children who underwent gross total resection was longer than the children in whom lesser degrees of resection were achieved (p = 0.015). The extent of the disease is a very important parameter found to be associated with survival. Patients with no evidence of disease after surgery had a mean survival of 123 months, compared with 82 months in patients with local residual disease and 55 months in patients with disseminated disease (p<0.001). By the univariate analysis, factors predicting poor outcome in our series were the presentation of disease with hormonal abnormalities, tumor location, and the extent of the disease, while the factors predicting a better outcome were age at the time of diagnosis, presentation of the disease with neurological deficit, and type of resection. By the multivariate analysis, the extent of the disease remained as the only strong adverse risk factor for survival (HR 2.06; 95% CI = 1.38–3.07; p<0.001).

Conclusions

With an organized and dedicated multidisciplinary team, the adequate outcomes can be achieved in a middle-income country setting. The presence of local residual disease after surgery and disseminated disease has a strong negative effect on survival.

The Survival and Prognostic Factors of Supratentorial Cortical Ependymomas: A Retrospective Cohort Study and Literature-Based Analysis

Aim

Survival rates and prognostic factors of cortical ependymomas (CEs) remain elusive. This study aimed to perform a comprehensive analysis of prognostic factors, treatment, and outcomes for patients with CEs based on institutional and literature case series.

Materials and Methods

Thirty patients with CEs from our department were included in this study. Furthermore, a systemic review of the literature yielded an additional 106 patients with CEs. Clinical data including patient age, sex, symptoms, tumor location, World Health Organization (WHO) grade, extent of surgery, radiation, recurrence, and survival were recorded and statistically analyzed.

Results

From January 2009 to October 2019, 30 (4.2%) cases were diagnosed as CEs in our department. These series consisted of 19 males and 11 females, 10 continuous patients after 2017 screened for C11orf95-RELA fusion, and 9 patients (90%) were RELA fusion positive. During the follow-up period, nine (30%) patients depicted tumor recurrence or progression; four (13.3%) patients died of tumor progression. The literature review yielded 106 CE cases, with additional 30 cases of our own collected for further analysis. Of these 136 cases, the frontal lobe (40%) was the most common location, and the average age was 22.6 ± 17.6 years. Anaplastic histology/WHO grade III tumors were identified in 68 (50%) patients. Statistically analysis demonstrated that extent of surgery and WHO tumor grade were significant prognostic factors in Kaplan–Meier log-rank testing and Cox proportional hazards models. Gross total resection (GTR) predicted longer progression-free survival (PFS) [P = 0.013, hazard ratio (HR) = 3.012, 95% confidence interval (CI) = 1.257–7.213] and overall survival (OS) (P = 0.003, HR = 5.322, 95% CI = 1.751–16.178). WHO grade III tumors had worse PFS (P = 0.002, HR = 5.17, 95% CI = 1.804–14.816) and OS (P = 0.025, HR = 5.640, 95% CI = 1.248–25.495).

Conclusion

CEs accounted for only 3.5 to 5.7% of ependymomas, with seizures the most common symptom and the frontal lobe the most frequent location. CEs may have higher rate of RELA fusions, but generally favorable prognosis. The extent of surgery and WHO tumor grade were significant prognostic factors for PFS and OS in multivariate analysis. GTTR or WHO grade II tumors had better overall outcome in patients with CEs.

Advances in the molecular classification of pediatric brain tumors: a guide to the galaxy

Central nervous system (CNS) tumors are the most common solid tumor in pediatrics, accounting for approximately 25% of all childhood cancers, and the second most common pediatric malignancy after leukemia. CNS tumors can be associated with significant morbidity, even those classified as low grade. Mortality from CNS tumors is disproportionately high compared to other childhood malignancies, although surgery, radiation, and chemotherapy have improved outcomes in these patients over the last few decades. Current therapeutic strategies lead to a high risk of side effects, especially in young children. Pediatric brain tumor survivors have unique sequelae compared to age-matched patients who survived other malignancies. They are at greater risk of significant impairment in cognitive, neurological, endocrine, social, and emotional domains, depending on the location and type of the CNS tumor. Next-generation genomics have shed light on the broad molecular heterogeneity of pediatric brain tumors and have identified important genes and signaling pathways that serve to drive tumor proliferation. This insight has impacted the research field by providing potential therapeutic targets for these diseases. In this review, we highlight recent progress in understanding the molecular basis of common pediatric brain tumors, specifically low-grade glioma, high-grade glioma, ependymoma, embryonal tumors, and atypical teratoid/rhabdoid tumor (ATRT). © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

A novel technique of serial biopsy in mouse brain tumour models

Biopsy is often used to investigate brain tumour-specific abnormalities so that treatments can be appropriately tailored. Dacomitinib (PF-00299804) is a tyrosine kinase inhibitor (TKI), which is predicted to only be effective in cancers where the targets of this drug (EGFR, ERBB2, ERBB4) are abnormally active. Here we describe a method by which serial biopsy can be used to validate response to dacomitinib treatment in vivo using a mouse glioblastoma model. In order to determine the feasibility of conducting serial brain biopsies in mouse models with minimal morbidity, and if successful, investigate whether this can facilitate evaluation of chemotherapeutic response, an orthotopic model of glioblastoma was used. Immunodeficient mice received cortical implants of the human glioblastoma cell line, U87MG, modified to express the constitutively-active EGFR mutant, EGFRvIII, GFP and luciferase. Tumour growth was monitored using bioluminescence imaging. Upon attainment of a moderate tumour size, free-hand biopsy was performed on a subgroup of animals. Animal monitoring using a neurological severity score (NSS) showed that all mice survived the procedure with minimal perioperative morbidity and recovered to similar levels as controls over a period of five days. The technique was used to evaluate dacomitinib-mediated inhibition of EGFRvIII two hours after drug administration. We show that serial tissue samples can be obtained, that the samples retain histological features of the tumour, and are of sufficient quality to determine response to treatment. This approach represents a significant advance in murine brain surgery that may be applicable to other brain tumour models. Importantly, the methodology has the potential to accelerate the preclinical in vivo drug screening process.

Genomics and epigenetics: A study of ependymomas in pediatric patients

OBJECTIVE

We identify chromosomal alterations, the methylation pattern and gene expression changes in pediatric ependymomas.

METHODS

CGH microarray, methylation and gene expression were performed through the Agilent platform. The results were analyzed with the software MatLab, MapViewer, DAVID, GeneCards and Hippie.

RESULTS

Amplification was found in 14q32.33, 2p22.3 and 8p22, and deletion was found in 8p11.23-p11.22 and 1q21.3. We observed 42.387 CpG islands with changes in their methylation pattern, in which we found 272 genes involved in signaling pathways related to carcinogenesis. We found 481 genes with altered expression. The genes IMMT, JHDMD1D, ASAH1, ZWINT, IPO7, GNAO1 and CISD3 were found to be altered among the three levels.

CONCLUSION

The 2p22.3, 8p11.23-p11.22 and 14q32.33 regions were identified as the most important; the changes in the methylation pattern related to cell cycle and cancer genes occurred in MIB2, FGF18 and ITIH5. The IPO7, GNAO1 and ASAH1 genes may play a major role in ependymoma development.

CCDC26, CDKN2BAS, RTEL1 and TERT Polymorphisms in pediatric brain tumor susceptibility

The role of genetic polymorphisms in pediatric brain tumor (PBT) etiology is poorly understood. We hypothesized that single nucleotide polymorphisms (SNPs) identified in genome-wide association studies (GWAS) on adult glioma would also be associated with PBT risk. The study is based on the Cefalo study, a population-based multicenter case-control study. Saliva DNA from 245 cases and 489 controls, aged 7-19 years at diagnosis/reference date, was extracted and genotyped for 29 SNPs reported by GWAS to be significantly associated with risk of adult glioma. Data were analyzed using unconditional logistic regression. Stratified analyses were performed for two histological subtypes: astrocytoma alone and the other tumor types combined. The results indicated that four SNPs, CDKN2BAS rs4977756 (p = 0.036), rs1412829 (p = 0.037), rs2157719 (p = 0.018) and rs1063192 (p = 0.021), were associated with an increased susceptibility to PBTs, whereas the TERT rs2736100 was associated with a decreased risk (p = 0.018). Moreover, the stratified analyses showed a decreased risk of astrocytoma associated with RTEL1 rs6089953, rs6010620 and rs2297440 (p trend = 0.022, p trend = 0.042, p trend = 0.029, respectively) as well as an increased risk of this subtype associated with RTEL1 rs4809324 (p trend = 0.033). In addition, SNPs rs10464870 and rs891835 in CCDC26 were associated with an increased risk of non-astrocytoma tumor subtypes (p trend = 0.009, p trend = 0.007, respectively). Our findings indicate that SNPs in CDKN2BAS, TERT, RTEL1 and CCDC26 may be associated with the risk of PBTs. Therefore, we suggest that pediatric and adult brain tumors might share common genetic risk factors and similar etiological pathways.

Myxopapillary ependymoma in children: a study of 11 cases and a comparison with the adult experience

BACKGROUND

Myxopapillary ependymomas (MEPN) are uncommon tumors of the central nervous system, mainly occurring within the conus medullaris-filum terminale. MEPNs can also present in the skin and underlying soft tissues of the sacrococcygeal region. The incidence of extramedullary MEPNs in children is unclear.

PROCEDURE

We retrospectively reviewed our institutional files for MEPN cases between the years 1990-2012. A total of 11 pediatric and 38 adult cases were identified and compared to determine differences between these two distinct age groups.

RESULTS

There were 40 (82%) tumors arising in the spine and nine (18%) in extramedullary sites. Pathologic examination revealed that extramedullary and spinal MEPNs were indistinguishable morphologically and immunophenotypically. Among the 11 children with MEPNs, seven had tumors presenting in extramedullary sites whereas only two adults (5%) had extramedullary tumors; this difference was highly significant (P < 0.0001). The lumbosacral portion of the spinal cord was the primary site for the remaining 40 MEPNs, four (10%) of which presented in children. One extramedullary MEPN (9%) recurred in a 45-year-old woman, and five (11%) of 40 spinal tumors recurred and/or metastasized; two of four children with spinal MEPNs developed recurrences and a manifestation to the aggressive nature of the latter tumor in the spinal cord of children.

CONCLUSIONS

Based upon our experience, MEPN in children is more likely to present in the extramedullary soft tissues of the sacrococcygeal region where its behavior is more indolent than those tumors arising in the spinal cord in children.

Cartilage differentiation in ependymoma: histogenetic considerations on a new case

The presence of cartilage in gliomas is a very unusual finding and has been mainly reported in ependymomas and in astrocytomas. A derivation of cartilage from neuroepithelial cells through a neuroepithelial-mesenchymal transition or directly from blood vessel-associated multipotent stromal elements has been proposed. We herein describe a further case of ependymoma with the presence of cartilage in a child affected by a tumor in the posterior fossa. In this case, only the last recurrence, characterized by focal areas of anaplasia, contained a nodule of cartilage. The immunohistochemical expression of fibronectin, tenascin-C, and CD44 was investigated, and the possible role of these molecules in the process of cartilage formation is discussed. Moreover, the literature on the subject is reviewed.