Molecular Classification of Medullobastomas by Whole Genome Expression Profiling.

BACKGROUND: Medulloblastoma (MB) is the most common malignant tumour of the central nervous system in children. MB is considered to be high risk tumour propensity to metastasize. In the Czech Republic, approximately 10-12 children are affected annually by this tumour. Recent progress in molecular diagnostics helps to refine the diagnosis and estimate clinical prognosis of the disease. Currently, MBs are subclassified into WNT-activated, SHH-activated, group 3, and 4 based on molecular pathways that drive their tumorigenesis. Each subtype differs in its histopathology, clinical features, genomic changes and gene expressions. The aim of our study is to classify patients MBs into four basic molecular groups and compare our results with published data. MATERIAL AND METHODS: In our study we analysed expression profiles using Affymetrix GeneChip Human Gene 1.0. ST Array (Thermo Fisher Scientific, MA, USA). As input material RNA extracted from the fresh frozen tissue was used. Molecular classification based on the method established by P. Northcott in 2011 was performed. RESULTS: From April 2015 to February 2019, 21 patients with MBs were included in our study. Median age of the patients at the time of diagnosis was 6 years, 14 boys and 7 girls were enrolled. Gene expression profiling and molecular classification of MBs was performed. Based on this methodology, we found the most frequently represented subgroup of MB was group 4 (9 patients, 43%), followed by group 3 (5 patients, 24%), SHH-activated MB (4 patients, 19%) and the least represented subgroup was WNT-activated MB (3 patients, 14%). Results of molecular subgroup classification of MBs were successfully correlated with histopathological findings and other molecular-genetic examinations. CONCLUSION: Molecular classification of MBs has been established in our institution allowing better understanding of this heterogeneous disease and helping clinicians in therapeutic planning in affected patients. This work was supported by the Czech Ministry of Health grant No. 16-33209A. All rights reserved.  he authors declare they have no potential confl icts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 1. 3. 2019 Accepted: 4. 3. 2019.

Effective Immunotherapy of Glioblastoma in an Adolescent with Constitutional Mismatch Repair-Deficiency Syndrome.

BACKGROUND: Individuals with constitutional mismatch repair-deficiency syndrome (CMMR-D) are characterised by early occurrence of colon cancer, haematological malignancies, and brain tumors (malignant gliomas, high-grade gliomas) in childhood, adolescence, and early adulthood. High mutational tumor burden is typical of glioblastoma in CMMR-D patients and could be a reason why this type of glioblastoma responds well to immunotherapies, including those that employ checkpoint inhibitors. OBSERVATION: We describe a case of an adolescent with CMMR-D that had been genetically proven by whole exome sequencing (c.2T>A/p.M1K and c.2521delT/p.W841fs PMS2 gene mutation). The patient presented successively with colon cancer and glioblastoma with a high mutational burden. The individualized glioblastoma therapy was based on the biological tumor profile and included immunotherapy with a combination of vaccination with autologous dendritic cells producing IL-12 and nivolumab, in addition to radiotherapy with metronomic temozolomide. The patient is still alive 21 months after the initial glioblastoma diagnosis and shows a complete therapeutic response documented by repeated magnetic resonance examinations. CONCLUSION: Individuals with CMMR-D should be regularly examined using established algorithms. Whole body magnetic resonance imaging can play a key role, because it enables the early diagnosis of malignancy during the asymptomatic period. Malignancies in CMMR-D patients usually exhibit a hypermutated genotype and respond to immunotherapy. Conventional glioblastoma therapy is only palliative. Patients can benefit from an individualized therapeutic plan based on the tumor biological profile. Extensive molecular analysis of the tumor tissue is necessary. Key words hereditary cancer predisposition syndromes - glioblastoma - whole exome sequencing - immunotherapy - vaccines - checkpoint inhibitors This study was supported by the research project of the Czech Ministry of Health AZV 16-33209A (Next generation sequencing and express profiling as diagnostic tools for personalized therapeutic plans in children with solid tumors). The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers. Submitted: 26. 9. 2018 Accepted: 18. 11. 2018.

NEUROFIBROMATOSIS TYPE 1 AND OPTIC PATHWAY GLIOMA.

PURPOSE: Evaluate the effectiveness of treatment of patients with optic pathway glioma. MATERIALS AND METHODS: Comparison of literature research on neurofibromatosis and optic pathway glioma with a cohort of pediatric patients treated at the Childrens Ophthalmology Clinic of the University Hospital in Brno from January 2013 until June 2018. DISCUSSION: The main challenge of this and other retrospective studies is variable intervals between ophthalmologic examinations. In some pediatric patients it is also difficult to objectively assess visual functions. The main risk factors are age at the time of treatment and tumor localization. Tumor progression itself does not always correlate with worse visual acuity outcomes, and it remains to be evaluated whether some patients would be better off without treatment. As of now, there are no clinical biomarkers able to predict impending visual acuity loss. CONCLUSION: The cohort outcome agrees with literature. Chemotherapy remains a treatment of choice and its most likely outcome is visual acuity stabilization. In order to properly evaluate the treatments effectiveness, better collaboration between medical specialists and regular standardized ophthalmology examinations are required.

[Identification of a Family with SUFU Germline Deletion Based on a Case of Desmoplastic Medulloblastoma in an Infant]. / Identifikace rodiny s nosicstvím germinální delece genu SUFU na podklade dia-gnózy desmoplastického meduloblastomu u batolete.

BACKGROUND: Medulloblastoma, an embryonal neuroectodermal tumor of the cerebellum, is the most common malignant brain tumor in children. There are approximately 15 cases diagnosed in the Czech Republic each year. The recent World Health Organization classification recognizes several histopathological subtypes of medulloblastoma: classical, desmoplastic/ nodular with its extensive-nodularity variant, and anaplastic/ large-cell variant. Further molecular analysis identified four basic subgroups of medulloblastoma: WNT, SHH, Group 3, and Group 4. The subgroup of SHH meduloblastoma is associated with somatic mutations of SHH, PTCH1, SUFU, SMO and TP53, while the most common mutations found in infants up to three years of age were PTCH1 and SUFU. The majority of medulloblastomas are sporadic diseases, whereas only about 5- 10% of all cases occur in connection with hereditary genetic syndromes. CASE: We present a case of a 21-months old girl diagnosed with a localized posterior fossa tumor. The histopathological examination revealed a desmoplastic/ nodular medulloblastoma. The treatment comprised a radical exstirpation of the tumor followed by adjuvant chemotherapy. With the use of array-CGH, a partial biallelic deletion of the SUFU gene (locus 10q24.32) was detected in the tumor DNA, whereas a monoallelic deletion was found in the peripheral lymphocyte DNA of the patient. These findings were confirmed by an independent qPCR method. Monoallelic germline deletion of SUFU was also identified in the patients mother, who was a healthy carrier. Pedigree of the family suggested a transition of the germline deletion of SUFU, since another brain tumors (including one case diagnosed before the age of three years) were identified in previous generations. CONCLUSION: Germline mutations in SUFU gene are believed to predispose to infant desmoplastic/ nodular medulloblastomas, basal cell carcinomas and meningiomas. The susceptibility gene shows autosomal dominant inheritance with an incomplete penetrance. There is no evidence-based surveillance strategy suggested for the carriers of germline SUFU mutations/ deletions so far. Our recommendation is based both on a family history of our patient and similar cases described in the literature. Since the germinal mutations in SUFU are responsible for up to 50% of all desmoplastic medulloblastomas in children under three years of age, genetic testing of SUFU should be encouraged in this population of patients.

[Profile of Activation of Tyrosine Kinases and MAP Kinases in Therapy of Maffucci Syndrome]. / Profil aktivace receptorových tyrozinkináz a mitogenem aktivovaných proteinkináz v terapii Maffucciho syndromu.

BACKGROUND: Maffucci syndrome is a rare congenital nonhereditary disease characterized by multiple hemangiomas and enchondromas, which may progress into malignancy. The causal therapy does not exist, and therapy is aimed at complications. The determination of appropriate therapy is complicated, and a multidisciplinary approach is often essential. CASE: Authors are presenting the case of a 20-year -old patient with Maffucci syndrome. During her life, multiple enchondromas and progressing hemangiomas have been revealed and they have caused many complications, such as limited movement, growth failure, pain, fluidothorax and ascites. A profile of phosphorylation of selected tyrosine kinases and MAP kinases from progressing hemangioma was performed and with consideration of the result, it led to change of treatment strategy with encouraging clinical response lasting for six months.

[Subependymal giant cell astrocytoma associated with tuberous sclerosis complex -  pharmacological treatment using mTOR inhibitors]. / Subependymální obrovskobunecný astrocytom u pacientu s tuberózní sklerózou -  farmakologická lécba mTOR inhibitory.

Tuberous sclerosis complex is a neurocutaneous syndrome that results from a germline mutation in TSC1 or TSC2 genes. The pathogenic activation of mTORC1 leads to the development of subependymal giant cell astrocytomas in patients with tuberous sclerosis complex. Blocking of the dysregulated pathway with mTOR inhibitors has the potential to reduce the volume of this low-grade brain tumor. This article reviews the current knowledge on the pharmacological treatment of subependymal giant cell astrocytomas. A longterm followup and early therapeutic intervention should lead to mortality and morbidity reduction and quality of life improvement in patients with tuberous sclerosis complex associated tumors.

Metronomic chemotherapy with the COMBAT regimen in advanced pediatric malignancies: a multicenter experience.

BACKGROUND: The outcome of children with refractory/relapsed malignancies remains poor and novel therapies are urgently required. One of the promising approaches is metronomic chemotherapy. We present the clinical results of 74 children with advanced solid tumors treated according to treatment recommendation with data registry in three European pediatric centers. METHODS: COMBAT (Combined Oral Metronomic Biodifferentiating Antiangiogenic Treatment) included low-dose daily temozolomide, etoposide, celecoxib, vitamin D, fenofibrate and retinoic acid. From 2004 to 2010, 74 children were enrolled. RESULTS: The 2-year overall survival (OS) was 43.1% (median 15.4, range 1.3-69.9 months). Of the 74 patients, 50 patients (68%) died and 24 are alive: 6 (8%) with progressive disease, 7 (9%) with stable disease/partial response and 11 (15%) in complete response. Median time to response was 6 months. Of 62 patients with initially measurable disease, 25 (40%) had radiological response or stable disease. Fourteen of 25 showing clinical benefit responded within the first 6 months. The treatment was well tolerated on an outpatient basis. Regarding non-hematological toxicity of grade ≥2, hepatotoxicity of grade 3 occurred in 8 children and grade 3 cheilitis in 16 children. CONCLUSION: COMBAT is a feasible and effective treatment option for patients with relapsing/refractory malignancies. The treatment is well tolerated with a low acute toxicity profile.

[Radiotherapy induced glioblastoma in a child previously treated for cerebellar medulloblastoma (case report and review of the literature)]. / Radioterapií indukovaný glioblastom u dítete léceného pro meduloblastom mozecku (kasuistika a prehled literatury).

Malignant gliomas represent the most frequent radiotherapy induced ("secondary") solid tumor. Their prognosis remains extremely poor despite of aggressive multimodal treatment. We present a case report of a 16 years old boy who developed cerebellar glioblastoma six years following the combined treatment for medulloblastoma. Clinical history, pathological and cytogenetic findings of the case are discussed along with treatment possibilities.

Central neurocytoma: the neuroradiological perspective.

BACKGROUND: Central neurocytoma (CN) represents a rare, relatively recently described primary central nervous system tumor. It ranks among intraventricular tumors due to its predominant location within the lateral brain ventricles. CN occurs mostly in young adults around the 3rd decade of life; almost a fifth of the cases are children under 18 years of age. OBJECTIVES: The authors present three cases of patients with histopathologically confirmed CN, emphasizing diagnostic imaging issues. A review of the literature concerning differential diagnosis and clinical and therapeutic aspects is also presented. CONCLUSION: Literature reports of CN comprise most likely case reports, small cohorts of patients, and meta-analytic studies due to the generally low incidence of this tumor. In the current paper, the authors summarize up-to-date knowledge of this rare disease on the background of their own observations. CN should be included in the list for differential diagnostics of intraventricular brain tumors, especially those located in lateral ventricles.

The optimization of sample treatment for spectral karyotyping with applications for human tumour cells.

Spectral karyotyping (SKY) represents an important tool for the investigation of the complex chromosomal rearrangements (CCRs) in many human malignancies which may be difficult to characterize by conventional banding techniques. The main goal of our work was to optimize the most important steps in the preparation of molecular cytogenetic slides for a SKY protocol. This approach consisted of optimization of both the aging procedure and protease pretreatment of the slides, with special regard given to the preservation of chromosome structure and shape, as well as to the intensity of hybridization signals. The best results were obtained with a chemical aging procedure using SSC or ethanol in combination with trypsin pretreatment applied at a higher concentration for a shorter period of pretreatment. A resulting protocol for SKY also applicable to human solid tumour cells was subsequently proposed. The practical potential of the SKY technique was demonstrated on examples of two types of human embryonal tumours--neuroblastoma and Wilms' tumour, in which some kinds of chromosomal aberrations were not detectable by means of classic cytogenetic methods.

Effect of retinoic acid on the actin cytoskeleton in HL-60 cells.

The cytoskeleton, in addition to its structural and kinetic functions, is also involved in modulating signal transfer in cell proliferation, differentiation and death. In some myeloid leukemic cell lines, the process of cell differentiation accompanied by apoptosis, can be induced by all-trans retinoic acid (ATRA). In this report, we describe the morphological changes in actin cytoskeleton, taking place during apoptosis in cells of the human leukemic HL-60 cell line. By using fluorescent microscopy, the morphology of microfilaments and the proportion of apoptotic cells in the cell populations untreated or treated with 10(-6) M ATRA were detected. Interphase HL-60 cells showed aggregations of short, thick microfilament bundles in the region between the plasma membrane and the nucleus. In comparison with both interphase and mitotic cells, the cells with apoptotic nuclear fragmentation showed a different organisation of the actin cytoskeleton. The following types of F-actin structures were observed: (i) Cells with a high number of large dots/patches of F-actin under the plasma membrane. These dots might be localised only in the part of the cell or occurred under the whole plasma membrane. This arrangement was often associated with a diffuse signal for F-actin. (ii) Cells with 3D-network of F-actin fibres through the cytoplasm between remnants of the cell nucleus. This 3D-structure probably played an important active role in the process of apoptotic bodies formation. (iii) Cells without any detectable signal for F-actin or cells with only a very low F-actin signal. Both of these showed typical apoptotic collapse of chromatin. It is concluded that the actin cytoskeleton is a dynamic structure actively involved in the executive phase of the process of apoptosis. It is suggested that the rearrangement of the microfilament network and its subsequent degradation are necessary for the main morphological changes of apoptotic cells, i.e., plasma membrane blebbing and apoptotic bodies formation.