Risk-Adapted Treatment Strategies with Pre-Irradiation Chemotherapy in Pediatric Medulloblastoma: Outcomes from the Polish Pediatric Neuro-Oncology Group.

Craniospinal irradiation (CSI) has been a major component of the standard of care treatment backbone for childhood medulloblastoma. However, chemotherapy regimens have varied based on protocol, patient age, and molecular subtyping. In one of the largest studies to date, we analyzed treatment outcomes in children with newly-diagnosed medulloblastoma treated with pre-irradiation chemotherapy followed by risk-adapted radiotherapy and maintenance chemotherapy. A total of 153 patients from the Polish Pediatric Neuro-Oncology Group were included in the analysis. The median age at diagnosis was 8.0 years, and median follow-up time was 6.4 years. Sixty-seven patients were classified as standard-risk and eighty-six as high-risk. Overall survival (OS) and event-free survival (EFS) for standard-risk patients at 5 years (±standard error) were 87 ± 4.3% and 84 ± 4.6%, respectively, while 5-year OS and EFS for high-risk patients were 81 ± 4.3% and 79 ± 4.5%, respectively. Only one patient had disease progression prior to radiotherapy. This study demonstrates promising survival outcomes in patients treated with pre-irradiation chemotherapy followed by risk-adapted CSI and adjuvant chemotherapy. Such an approach may be useful in cases where the initiation of radiotherapy may need to be delayed, a common occurrence in many institutions globally.

Constitutional mosaicism of a de novo TP53 mutation in a patient with bilateral choroid plexus carcinoma.

Choroid plexus tumors (CPT) constitute 2%-5% of all pediatric brain tumors and include high grade choroid plexus carcinoma (CPC). About 40% of CPC patients harbor germline TP53 mutations, associated with diminished survival rates. However, the number of TP53 carriers might be underestimated due to suboptimal ability of Sanger sequencing to identify mosaicism. We describe an 18-month-old boy with ultra-rare, bilateral disseminated CPC and negative family history of cancer. Next generation sequencing (NGS) revealed constitutional mosaicism of de novo TP53 mutation, which was barely detectable by Sanger sequencing. This is the first description of a de novo TP53 mutation mosaicism in a patient with CPC. Up to now four cases of de novo TP53 mutations in CPC patients have been described but none of them were mosaic. Since TP53 mutation mosaicism may have an impact on management of patients and predisposition to other cancers, a reliable method of identification is important. Our results highlight the utility of high-throughput technologies in detection of potentially important genetic markers.

Altered MicroRNA Expression Is Associated with Tumor Grade, Molecular Background and Outcome in Childhood Infratentorial Ependymoma.

BACKGROUND: Ependymal tumors are the third most common group of brain tumors in children, accounting for about 10% of all primary brain neoplasms. According to the current WHO classification, they comprise four entities with the most frequent ependymoma and anaplastic ependymoma. The most of pediatric tumors are located within the posterior fossa, with a tendency to infiltrate the vital brain structures. This limits surgical resection and poses a considerable clinical problem. Moreover, there are no appropriate outcome prognostic factors besides the extent of surgical resection. Despite definition of molecular subgroups, the majority of childhood ependymomas present a balanced genome, which makes it difficult to establish molecular prognostic factors. METHODS: The purpose of our study was to explore whether miRNA expression could be used as prognostic markers in pediatric infratentorial ependymomas. We also performed a mRNA expression pattern analysis of NELL2 and LAMA2 genes, with immunohistochemical illustrations of representative cases. The miRNA and mRNA expression was measured in 53 pediatric infratentorial ependymomas using a real-time quantitative PCR. RESULTS: Three miRNAs were shown to efficiently differentiate between grade II and III ependymomas: miR-17-5p, miR-19a-3p, and miR-106b-5p. Survival analysis showed that the probabilities of overall (p = 0.036) and event-free survival (p = 0.002) were reduced with higher than median miRNA expression levels of miR-17-5p. Using multivariate analysis adjusted for patient's age, sex, tumor grade and localization, we showed statistically significant associations with event-free survival (p = 0004) and borderline statistical significance with overall survival (p = 0.057) for miR-17-5p. Correlation analysis of miR-19a, miR-17-5p, miR-106b revealed that their expression levels were significantly correlated with EZH2 expression, suggested marker of PFA ependymomas. Furthermore, lower expression level of LAMA2 mRNA was shown to be associated with an increased risk of death in covariate-adjusted analyses. CONCLUSIONS: Our data provide a better understanding of pediatric ependymoma and suggests the presence of plausible molecular biomarkers connected with the outcome.

Upregulation of mitogen-activated protein kinase in ganglioglioma.

Ganglioglioma (GG) is a low-grade neoplasm, often associated with intractable epilepsy in pediatric patients. Available data suggest a relationship between GG and other glioneuronal lesions. So far, little is known about activation of kinases belonging to the mTor (mammalian target of rapamycin) pathway, although its upregulation is often found in brain tumors. Involvement of mTor kinase is responsible for excessive proliferation. In the current study we focused on the possible role of the Erk/Mapk (extracellular-signal-regulated kinase/mitogen-activated protein kinase) pathway in GG development. Eight GG tumors were resected from pediatric patients. Collected data reveal activation of proteins from the Erk pathway: Mek (extracellular regulated protein kinase kinase/mitogen-activated protein kinase kinase), Erk, Rsk1 (ribosomal S6 kinase 1), Rheb (Ras homolog enriched in brain) and Msk1 (mitogen- and stress-activated protein kinase 1), as detected by the western blot method. Moreover, activation of other proteins upstream of mTor - IGF-1R ß (insulin-like growth factor 1ß receptor), INR ß (insulin receptor ß), Akt/PKB (protein kinase B) - or downstream - 4E-BP1 (eukaryotic translation initiation factor 4E-binding protein 1) and rpS6 (ribosomal protein S6) - was also confirmed.

[Children with neurofibroma type 1 treated in the Children's Memorial Health Institute]. / Dzieci z neurofibromatoza typu 1 (NF1--choroba Recklinghausena) w materiale Instytutu "Pomnik--Centrum Zdrowia Dziecka".

UNLABELLED: Neurofibromatosis type I (NF1) is a relatively frequent autosomal dominant disorder with different manifestations from mild cosmetic problems to severe disease requiring multidisciplinary treatment. THE AIM of our study was lo analyze types of disorders in paediatric population of NF1 patients treated in the Children's Memorial Health Institute and to present the schedule of care adopted in our institution. MATERIAL AND METHODS: Medical records of 130 children, 70 girls and 60 boys aged from 1 year to 20 years 3 ms treated in the Children's Memorial Health Institute were analyzed. Type of mutation (familial or sporadic), age at diagnosis, type and frequency of disorders in the whole group of patients and in the familial and sporadic types were assessed. RESULTS: The familial type of NF1 was found in 58 patients, among whom there were, 23 patients from 10 families. It was sporadic in 40 pts and in 32 the type of mutation is unknown. The age at diagnosis ranged from 3 months to 17 years, median 6 years. The most frequent disorders were: T2-weighted hyperintensities of the white matter in 77 pts (59%), schooling problems in 60 pts (46%), skeletal deformations in 49 pts (37%), dysmorphia in 39 pts (30%), hyperactivity in 34 pts (26%), epilepsy in 29 pts (22%). There was a correlation between white matter hyperintensities and the presence of optic nerves gliomas (71%), schooling problems (58%), hyperactivity (77%) and dysarthria (85%). In 65 pts (53%) optic nerve gliomas were found, 45 patients required treatment. Plexiform neurofibroma requiring treatment was found in 25 pts (19%,), 6 had intraspinal penetration and in 4 spine compression was observed. Two patients were diagnosed with ganglioneuroma. Malignant tumours were found in 7 pts (5%), with a prevalence of soft tissues sarcomas. Skeletal disorders occurred more frequently in tNFl sporadic type than in familial cases (p=0.05). Based on our experience a management protocol was formulated. At the time of diagnosis this includes examination by the oncologist, neurologist, ophthalmologist, geneticist and additional investigations: abdominal ultrasound, chest X-rays, MR of the brain; found disorders indicate further consultations and studies. The check-up should be repeated annually and include all previous studies that revealed any abnormalities. CONCLUSIONS: 1. Diagnosis of NF1 is delayed until complications of the disease occur. 2. In the studied group skeletal disorders were more frequent in the sporadic than in the familial type. 3. The paediatric population with NF1 varies from the adult NF1 patients in type of disorders, diagnostic and treatment requirements. Therefore there is a need for different care standards in the two groups. 4. The knowledge about NF1 and the standards of care should be transferred to general practitioners in order to diagnose these patients early and to refer them to specialized centres.

[Treatment results of children and adolescents with brain stem tumours. Own experiences]. / Wyniki leczenia dzieci i mlodziezy z guzami pnia mózgu--doswiadczenia wlasne.

INTRODUCTION: Despite progress in neuro-oncology, treatment results of children and adolescents with brain stem tumours remain poor. There are also controversies concerning the role of chemotherapy in the treatment of these tumours. THE AIM of our study was to analyze treatment results of patients with brain stem tumours treated with radiotherapy alone and with the addition of chemotherapy and to assess which chemotherapy protocol is the most efficient. MATERIAL, METHODS: Between 1981-2004, 126 patients were treated in our department. The patients were divided into 2 groups according to treatment methods applied. The first group consisted of 49 patients treated with radiotherapy alone. In the second group 77 patients were irradiated and received chemotherapy. Overall survival (OS) at 1 and 5 years was analyzed in both groups. The efficacy of treatment of patients from the second group was assessed by evaluating reaction to radiotherapy, to different chemotherapy protocols and duration of tumour regression. Additionally OS was assessed separately for patients with low grade gliomas treated in the second group. RESULTS: Seven out of 49 patients from the first group are alive with a follow up from 8 years 9 months to 24 years, median 6 years 7 months. In the second group, 25 out of 77 patients are alive with the follow up from 7 months to 8 years 2 months, median--l year 7 months. OS at l and 5 years for patients treated with radiotherapy alone is 48 and 14% and for those receiving additionally irradiation 59 and 18% respectively (statistically insignificant). Best tumour response was achieved in 42% of patients with radiotherapy but in 75% of cases regression lasted from 2 weeks to l year 3 months, median 4 months. Addition of chemotherapy consisting of cisplatinum and temozolamide resulted in tumour regression in 27% of patients lasting from 4 weeks to 4 years 5 months, median 4 months. OS for patients with LGG was 34.6% at 5 years. CONCLUSIONS: 1. Radiotherapy in brain stem tumours allows to achieve tumour regression but short duration of remission and poor final outcome forces to search for other, effective treatment. 2. Patients with brain stem tumours may benefit from chemotherapy in terms of prolonging survival. 3. Chemotherapy consisting of temozolamide and cisplatinum seems to be promising and might add to improvement of treatment results, but further clinical studies are needed. 4. Patients with low grade gliomas of the brain stem constitute a separate group with a better prognosis.