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Abstract
Embryonal brain tumors are a heterogeneous group of neoplasms united by the presence of poorly differentiated stem-like cells. Molecular details are increasingly being used to separate them into biologically and clinically meaningful groups. For medulloblastoma, integrated mRNA expression profiling and DNA analysis by a number of research groups defines 4-6 distinctive molecular variants. A subset with prominent Wnt activity is associated with good clinical outcomes and classic histology. Medulloblastomas showing a Hedgehog gene expression signature are frequently of the desmoplastic/nodular subtype. Interestingly, Hedgehog activity is found in tumors arising either in infants or older teenagers and adults. The association of clinically aggressive medulloblastoma with MYC expression, large cell/anaplastic change and high levels of photoreceptor differentiation transcripts has also been noted in several studies. Immunohistochemical analysis of just one or two genes per molecular medulloblastoma variant may be sufficient for accurate classification, and this would be of great practical utility if validated. Advances have also been made in the classification of central nervous system (CNS) Primitive Neuroectodermal Tumors (PNET), as several groups have identified an amplicon at chromosome 19q13.41-42, which appears to define a unique PNET subtype associated with prominent true rosettes, young age and very poor outcomes.
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Affiliation(s)
- Charles G Eberhart
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Md 21205, USA.
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52
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Bone morphogenetic protein-7 is a MYC target with prosurvival functions in childhood medulloblastoma. Oncogene 2011; 30:2823-35. [PMID: 21317922 DOI: 10.1038/onc.2011.10] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Medulloblastoma (MB) is the most common malignant brain tumor in children. It is known that overexpression and/or amplification of the MYC oncogene is associated with poor clinical outcome, but the molecular mechanisms and the MYC downstream effectors in MB remain still elusive. Besides contributing to elucidate how progression of MB takes place, most importantly, the identification of novel MYC-target genes will suggest novel candidates for targeted therapy in MB. A group of 209 MYC-responsive genes was obtained from a complementary DNA microarray analysis of a MB-derived cell line, following MYC overexpression and silencing. Among the MYC-responsive genes, we identified the members of the bone morphogenetic protein (BMP) signaling pathway, which have a crucial role during the development of the cerebellum. In particular, the gene BMP7 was identified as a direct target of MYC. A positive correlation between MYC and BMP7 expression was documented by analyzing two distinct sets of primary MB samples. Functional studies in vitro using a small-molecule inhibitor of the BMP/SMAD signaling pathway reproduced the effect of the small interfering RNA-mediated silencing of BMP7. Both approaches led to a block of proliferation in a panel of MB cells and to inhibition of SMAD phosphorylation. Altogether, our findings indicate that high MYC levels drive BMP7 overexpression, promoting cell survival in MB cells. This observation suggests the potential relevance of targeting the BMP/SMAD pathway as a novel therapeutic approach for the treatment of childhood MB.
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53
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Zakrzewska M, Zakrzewski K, Grešner SM, Piaskowski S, Zalewska-Szewczyk B, Liberski PP. Polycomb genes expression as a predictor of poor clinical outcome in children with medulloblastoma. Childs Nerv Syst 2011; 27:79-86. [PMID: 20717685 PMCID: PMC3015167 DOI: 10.1007/s00381-010-1260-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 07/30/2010] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Medulloblastoma is the most frequent type of embryonal tumor in the pediatric population, accounting for 20-25% of all brain tumors in children. Recently, the suspected contribution of the Polycomb group (PcG) genes in medulloblastoma development was described. PcG genes play an important role in developmental processes; they are also involved in the self-renewal of hematopoietic and neural stem cells as well as in malignant transformation. PURPOSE In this study, we evaluated the expression of BMI1and PCGF2, members of family of PcG genes, and their potential target, MYC oncogene, and analyzed their association with demographic and clinical data. MATERIALS AND METHODS Thirty-one children (18 males and 13 females, aged from 0.4 to 17 years) with medulloblastoma were included in this study. The gene's expression level was measured by quantitative real-time PCR, obtained using the two-color multiplexing technique. RESULTS We found that the higher expression levels of BMI1 and PCGF2 genes were associated with significantly decreased patient survival (p = 0.02 and p = 0.012, respectively). Significant differences between gender were found, with a higher expression level of the PCGF2 gene observed among females (p = 0.02). CONCLUSION Our analysis showed correlation between BMI1 and PCGF2 gene's expression and survival in children with medulloblastoma.
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Affiliation(s)
- Magdalena Zakrzewska
- Department of Molecular Pathology and Neuropathology, Chair of Oncology, Medical University of Łódź, Czechosłowacka 8/10, Łódź, Poland.
| | - Krzysztof Zakrzewski
- Department of Neurosurgery, Polish Mother’s Memorial Hospital Research Institute, Rzgowska 281/289, 93-338 Łódź, Poland
| | - Sylwia M. Grešner
- Department of Molecular Pathology and Neuropathology, Chair of Oncology, Medical University of Łódź, Czechosłowacka 8/10, 92-216 Łódź, Poland
| | - Sylwester Piaskowski
- Department of Molecular Pathology and Neuropathology, Chair of Oncology, Medical University of Łódź, Czechosłowacka 8/10, 92-216 Łódź, Poland
| | - Beata Zalewska-Szewczyk
- Department of Pediatrics, Oncology, Hematology and Diabetology, 1st Chair of Pediatrics, Medical University of Łódź, Sporna 36/50, 91-738 Łódź, Poland
| | - Paweł P. Liberski
- Department of Molecular Pathology and Neuropathology, Chair of Oncology, Medical University of Łódź, Czechosłowacka 8/10, 92-216 Łódź, Poland
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54
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Molecular diagnostics of CNS embryonal tumors. Acta Neuropathol 2010; 120:553-66. [PMID: 20882288 DOI: 10.1007/s00401-010-0751-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2010] [Revised: 09/20/2010] [Accepted: 09/22/2010] [Indexed: 12/18/2022]
Abstract
Tremendous progress has recently been made in both molecular subgrouping, and the establishment of prognostic biomarkers for embryonal brain tumors, particularly medulloblastoma. Several prognostic biomarkers that were initially identified in retrospective cohorts of medulloblastoma, including MYC and MYCN amplification, nuclear β-catenin accumulation, and chromosome 17 aberrations have now been validated in clinical trials. Moreover, molecular subgroups based on distinct transcriptome profiles have been consistently reported from various groups on different platforms demonstrating that the concept of distinct medulloblastoma subgroups is very robust. Well-described subgroups of medulloblastomas include tumors showing wingless signaling pathway (Wnt) activation, and another characterized by sonic hedgehog pathway activity. Two or more additional subgroups were consistently reported to contain the vast majority of high-risk tumors, including most tumors with metastatic disease at diagnosis and/or large cell/anaplastic histology. Several years ago, atypical teratoid rhabdoid tumor (AT/RT) was recognized as a separate entity based on its distinct biology and particularly aggressive clinical behavior. These tumors may occur supra or infratentorially and are usually found to have genetic alterations of SMARCB1 (INI1/hSNF5), a tumor suppressor gene located on chromosome 22q. Subsequent loss of SMARCB1 protein expression comprises a relatively specific and sensitive diagnostic marker for AT/RT. For CNS primitive neuroectodermal tumors (CNS PNETs), a consistent finding has been that they are molecularly distinct from medulloblastoma. Furthermore, a distinct fraction of CNS PNETs with particularly poor prognosis only occurring in young children was delineated, which was previously labeled ependymoblastoma or embryonal tumor with abundant neuropil and true rosettes (ETANTR) and which is morphologically characterized by the presence of multilayered "ependymoblastic" rosettes. This group of tumors shows a unique cytogenetic abnormality not seen in other brain tumors: focal amplification of a micro-RNA cluster at chromosome 19q13.42, which has never been found to be amplified in other CNS PNETs, medulloblastoma or AT/RT. In summary, these consistent findings have significantly contributed to our ability to sub-classify embryonal brain tumors into clinically and biologically meaningful strata and, for some of the subgroups, have led to the identification of specific targets for future development of molecularly targeted therapies.
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55
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Zhou L, Picard D, Ra YS, Li M, Northcott PA, Hu Y, Stearns D, Hawkins C, Taylor MD, Rutka J, Der SD, Huang A. Silencing of thrombospondin-1 is critical for myc-induced metastatic phenotypes in medulloblastoma. Cancer Res 2010; 70:8199-210. [PMID: 20876797 DOI: 10.1158/0008-5472.can-09-4562] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mechanisms by which c-Myc (Myc) amplification confers aggressive medulloblastoma phenotypes are poorly defined. Here, we show using orthotopic models that high Myc expression promotes cell migration/invasion and induces metastatic tumors, which recapitulate aggressive histologic features of Myc-amplified primary human medulloblastoma. Using ChIP-chip analysis, we identified cell migration and adhesion genes, including Tsp-1/THBS1, ING4, PVRL3, and PPAP2B, as Myc-bound loci in medulloblastoma cells. Expression of Tsp-1 was most consistently and robustly diminished in medulloblastoma cell lines and primary human tumors with high Myc expression (n = 101, P = 0.032). Strikingly, stable Tsp-1 expression significantly attenuated in vitro transformation and invasive/migratory properties of high Myc-expressing medulloblastoma cells without altering cell proliferation, whereas RNA interference-mediated Myc knockdown was consistently accompanied by increased Tsp-1 levels and reduced cell migration and invasion in medulloblastoma cells. Chromatin immunoprecipitation (ChIP) assays revealed colocalization of Myc and obligate partner Max and correlated diminished RNA polymerase II occupancy (∼3-fold decrease, P < 0.01) with increased Myc binding at a core Tsp-1 promoter. Reporter gene and/or gel shift assays confirmed direct repression of Tsp-1 transcription by Myc and also identified JPO2, a Myc interactor associated with metastatic medulloblastoma, as a cofactor in Myc-mediated Tsp-1 repression. These findings indicate the Myc-regulatory network targets Tsp-1 via multiple mechanisms in medulloblastoma transformation, and highlight a novel critical role for Tsp-1 in Myc-mediated aggressive medulloblastoma phenotypes.
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Affiliation(s)
- Limei Zhou
- Sonia and Arthur Labatt Brain Tumor Research Centre, Hospital for Sick Children, University Avenue, Toronto, Ontario, Canada M5G 1X8
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56
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Childhood medulloblastoma: novel approaches to the classification of a heterogeneous disease. Acta Neuropathol 2010; 120:305-16. [PMID: 20652577 DOI: 10.1007/s00401-010-0726-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 07/12/2010] [Accepted: 07/12/2010] [Indexed: 10/19/2022]
Abstract
Increasing recognition of pediatric medulloblastoma as a heterogeneous disease, with histopathological and molecular variants that have distinct biological behaviors, will impact how the disease is classified and treated. A combination of clinicopathological evaluation and assays based on molecular subgroups of disease will allow stratification of patients into risk groups and a more tailored approach to therapy. Patients with low-risk disease could be treated with de-escalated adjuvant therapy to maximize cure while reducing long-term adverse effects, and novel therapies could be sought for patients with high-risk disease. My review encompasses a brief overview of the clinical landscape, the current World Health Organization (WHO) classification of medulloblastoma, the status of molecular subgroups, and how potential stratification schemes might impact pathologists and their practice.
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57
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Onvani S, Etame AB, Smith CA, Rutka JT. Genetics of medulloblastoma: clues for novel therapies. Expert Rev Neurother 2010; 10:811-23. [PMID: 20420498 DOI: 10.1586/ern.10.31] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Medulloblastoma is the most common malignant brain tumor in children. Current medulloblastoma therapy entails surgery, radiation and chemotherapy. The 5-year survival rate for patients ranges from 40 to 70%, with most survivors suffering from serious long-term treatment-related sequelae. Additional research on the molecular biology and genetics of medulloblastoma is needed to identify robust prognostic markers for disease-risk stratification, to improve current treatment regimes and to discover novel and more effective molecular-targeted therapies. Recent advances in molecular biology have led to the development of powerful tools for the study of medulloblastoma tumorigenesis, which have revealed new insights into the molecular underpinnings of this disease. Here we discuss the signaling pathway alterations implicated in medulloblastoma pathogenesis, the techniques used in molecular profiling of these tumors and recent molecular subclassification schemes. Particular emphasis is given to the identification of novel molecular targets for less toxic, patient-tailored therapeutic approaches.
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Affiliation(s)
- Sara Onvani
- The Hospital for Sick Children, Ontario, Canada
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58
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Zitterbart K, Filkova H, Tomasikova L, Necesalova E, Zambo I, Kantorova D, Slamova I, Vranova V, Zezulkova D, Pesakova M, Pavelka Z, Veselska R, Kuglik P, Sterba J. Low-level copy number changes of MYC genes have a prognostic impact in medulloblastoma. J Neurooncol 2010; 102:25-33. [PMID: 20607354 DOI: 10.1007/s11060-010-0289-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 06/21/2010] [Indexed: 01/22/2023]
Abstract
High-level amplifications of MYC genes are associated with poor outcomes in childhood medulloblastoma (MB). However, the occurrence of MYCN and MYCC copy number increases below the intense amplification pattern is rarely reported, and its clinical impact has not yet been determined. Here, we describe this phenomenon and its prognostic significance in a cohort of 29 MB patients. Using interphase fluorescence in situ hybridization (I-FISH), low-level copy number alterations, i.e. gain of MYCN, were shown in 5/27 (19%) samples, whereas amplification was revealed in only 1/27 (4%) samples. MYCC gain was revealed in 6/29 (21%) MB, while amplification was disclosed in only 2/29 (7%). Hyperploidy and co-incidence of gains in both MYC loci were frequently observed in samples with copy number aberrations. Survival analysis has clearly shown that MYC copy number increases are associated with lowered event-free survival and overall survival in MB. In the case of MYCN, this negative correlation was statistically significant. We conclude that limited numerical alterations in loci 2p24 (MYCN) and 8q24 (MYCC), as assessed by I-FISH, are present in MB with a higher frequency than high-level amplifications. Poor prognoses were observed in patients with copy number increases in MYC genes. Our data illustrate the importance of further investigations in multicenter trials to better refine the emerging genomic-based prognostic stratification in MB.
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Affiliation(s)
- Karel Zitterbart
- Department of Pediatric Oncology, University Hospital Brno, Masaryk University, Cernopolni 9, 613 00 Brno, Czech Republic.
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59
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Swartling FJ, Grimmer MR, Hackett CS, Northcott PA, Fan QW, Goldenberg DD, Lau J, Masic S, Nguyen K, Yakovenko S, Zhe XN, Gilmer HCF, Collins R, Nagaoka M, Phillips JJ, Jenkins RB, Tihan T, Vandenberg SR, James CD, Tanaka K, Taylor MD, Weiss WA, Chesler L. Pleiotropic role for MYCN in medulloblastoma. Genes Dev 2010; 24:1059-72. [PMID: 20478998 DOI: 10.1101/gad.1907510] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Medulloblastoma (MB) is the most common malignant brain tumor of childhood. Sonic Hedgehog (SHH) signaling drives a minority of MB, correlating with desmoplastic pathology and favorable outcome. The majority, however, arises independently of SHH and displays classic or large cell anaplastic (LCA) pathology and poor prognosis. To identify common signaling abnormalities, we profiled mRNA, demonstrating misexpression of MYCN in the majority of human MB and negligible expression in normal cerebella. We clarified a role in pathogenesis by targeting MYCN (and luciferase) to cerebella of transgenic mice. MYCN-driven MB showed either classic or LCA pathologies, with Shh signaling activated in approximately 5% of tumors, demonstrating that MYCN can drive MB independently of Shh. MB arose at high penetrance, consistent with a role for MYCN in initiation. Tumor burden correlated with bioluminescence, with rare metastatic spread to the leptomeninges, suggesting roles for MYCN in both progression and metastasis. Transient pharmacological down-regulation of MYCN led to both clearance and senescence of tumor cells, and improved survival. Targeted expression of MYCN thus contributes to initiation, progression, and maintenance of MB, suggesting a central role for MYCN in pathogenesis.
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Affiliation(s)
- Fredrik J Swartling
- University of California at San Francisco, San Francisco, California 94158, USA
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60
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Huse JT, Holland EC. Targeting brain cancer: advances in the molecular pathology of malignant glioma and medulloblastoma. Nat Rev Cancer 2010; 10:319-31. [PMID: 20414201 DOI: 10.1038/nrc2818] [Citation(s) in RCA: 530] [Impact Index Per Article: 37.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Malignant brain tumours continue to be the cause of a disproportionate level of morbidity and mortality across a wide range of individuals. The most common variants in the adult and paediatric populations - malignant glioma and medulloblastoma, respectively - have been the subject of increasingly intensive research over the past two decades that has led to considerable advances in the understanding of their basic biology and pathogenesis. This Review summarizes these developments in the context of the evolving notion of molecular pathology and discusses the implications that this work has on the design of new treatment regimens.
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Affiliation(s)
- Jason T Huse
- Departments of Pathology, 408 East 69th Street (Z1304), New York, NY 10065, USA
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61
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Abstract
Medulloblastoma, a primitive neuro-ectodermal tumour that arises in the posterior fossa, is the most common malignant brain tumour occurring in childhood. Over the past half century, the long-term survival for children with medulloblastoma has improved remarkably from a certain fatal diagnosis to a cancer that is often curable. Although overall survival for children with non-disseminated and non-anaplastic medulloblastoma can approach 80%, the current multidisciplinary therapeutic approach is not without long-term sequelae. Chemotherapy has improved the long-term survival and allowed for reductions in the amount of radiation given, thereby reducing some of the long-term toxicities. In this review, we describe the current understanding of the basic biology of medulloblastoma and report on the current active chemotherapeutic agents utilized in medulloblastoma therapy. Ultimately, our understanding of the basic biology of medulloblastoma may lead to further advances in therapy by providing targets that are more specific and potentially less toxic.
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Affiliation(s)
- Laura J Klesse
- Division of Pediatric Hematology-Oncology, Department of Pediatrics, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9063, USA.
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62
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Elamin MH, Shinwari Z, Hendrayani SF, Al-Hindi H, Al-Shail E, Khafaga Y, Al-Kofide A, Aboussekhra A. Curcumin inhibits the Sonic Hedgehog signaling pathway and triggers apoptosis in medulloblastoma cells. Mol Carcinog 2010; 49:302-14. [PMID: 20025076 DOI: 10.1002/mc.20604] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Medulloblastoma is an aggressive primary brain tumor that arises in the cerebellum of children and young adults. The Sonic Hedgehog (Shh) signaling pathway that plays important roles in the pathology of this aggressive disease is a promising therapeutic target. In the present report we have shown that curcumin has cytotoxic effects on medulloblastoma cells. Curcumin suppressed also cell proliferation and triggered cell-cycle arrest at G(2)/M phase. Moreover, curcumin inhibited the Shh-Gli1 signaling pathway by downregulating the Shh protein and its most important downstream targets GLI1 and PTCH1. Furthermore, curcumin reduced the levels of beta-catenin, the activate/phosphorylated form of Akt and NF-kappaB, which led to downregulating the three common key effectors, namely C-myc, N-myc, and Cyclin D1. Consequently, apoptosis was triggered by curcumin through the mitochondrial pathway via downregulation of Bcl-2, a downstream anti-apoptotic effector of the Shh signaling. Importantly, the resistant cells that exhibited no decrease in the levels of Shh and Bcl-2, were sensitized to curcumin by the addition of the Shh antagonist, cyclopamine. Furthermore, we have shown that curcumin enhances the killing efficiency of nontoxic doses of cisplatin and gamma-rays. In addition, we present clear evidence that piperine, an enhancer of curcumin bioavailability in humans, potentiates the apoptotic effect of curcumin against medulloblastoma cells. This effect was mediated through strong downregulation of Bcl-2. These results indicate that curcumin, a natural nontoxic compound, represents great promise as Shh-targeted therapy for medulloblastomas.
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Affiliation(s)
- Maha H Elamin
- Department of Biological and Medical Research, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
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63
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Williams RD, Al-Saadi R, Chagtai T, Popov S, Messahel B, Sebire N, Gessler M, Wegert J, Graf N, Leuschner I, Hubank M, Jones C, Vujanic G, Pritchard-Jones K. Subtype-specific FBXW7 mutation and MYCN copy number gain in Wilms' tumor. Clin Cancer Res 2010; 16:2036-45. [PMID: 20332316 DOI: 10.1158/1078-0432.ccr-09-2890] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
PURPOSE Wilms' tumor (WT), the most common pediatric renal malignancy, is associated with mutations in several well-characterized genes, most notably WT1, CTNNB1, WTX, and TP53. However, the majority of cases do not harbor mutations in these genes. We hypothesized that additional drivers of tumor behavior would be contained within areas of consistent genomic copy number change, especially those associated with the WT risk groups defined by the International Society of Paediatric Oncology (SIOP). EXPERIMENTAL DESIGN We analyzed high-resolution (Affymetrix 250K single nucleotide polymorphism array) genomic copy number profiles of over 100 tumors from selected risk groups treated under the SIOP protocols, further characterizing genes of interest by sequencing, Multiplex Ligation-dependent Probe Amplification, or fluorescence in situ hybridization. RESULTS We identified FBXW7, an E3 ubiquitin ligase component, as a novel Wilms' tumor gene, mutated or deleted in approximately 4% of tumors examined. Strikingly, 3 of 14 (21%) of tumors with epithelial type histology after neoadjuvant chemotherapy had FBXW7 aberrations, whereas a fourth WT patient had germline mutations in both FBXW7 and WT1. We also showed that MYCN copy number gain, detected in 9 of 104 (8.7%) of cases, is relatively common in WT and significantly more so in tumors of the high risk diffuse anaplastic subtype (6 of 19, 32%). CONCLUSIONS Because MYCN is itself a target of FBXW7-mediated ubiquitination and degradation, these results suggest that a common pathway is dysregulated by different mechanisms in various WT subtypes. Emerging therapies that target MYCN, which is amplified in several other pediatric cancers, may therefore be of value in high risk Wilms' tumor.
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Affiliation(s)
- Richard D Williams
- Section of Paediatric Oncology, Institute of Cancer Research, Sutton, Surrey, United Kingdom
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64
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Ciara E, Piekutowska-Abramczuk D, Popowska E, Grajkowska W, Barszcz S, Perek D, Dembowska-Bagińska B, Perek-Polnik M, Kowalewska E, Czajńska A, Syczewska M, Czornak K, Krajewska-Walasek M, Roszkowski M, Chrzanowska KH. Heterozygous germ-line mutations in the NBN gene predispose to medulloblastoma in pediatric patients. Acta Neuropathol 2010; 119:325-34. [PMID: 19908051 DOI: 10.1007/s00401-009-0608-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Revised: 10/30/2009] [Accepted: 10/31/2009] [Indexed: 01/23/2023]
Abstract
The NBN (NBS1) gene belongs to a group of double-strand break repair genes. Mutations in any of these genes cause genome instability syndromes and contribute to carcinogenesis. NBN gene mutations cause increased tumor risk in Nijmegen breakage syndrome (NBS) homozygotes as well as in NBN heterozygotes. NBS patients develop different types of malignancies; among solid tumors, medulloblastoma (MB), an embryonal tumor of the cerebellum, has been reported most frequently. The majority of medulloblastomas occur sporadically, some of them manifest within familial cancer syndromes. Several signaling pathways are known to be engaged in hereditary and sporadic MB. The aim of our study was to identify mutations in selected exons of the NBN gene and to determine the frequency of the most common NBN gene mutations in pediatric patients with different types of medulloblastoma. We screened a total of 104 patients with MB and identified 7 heterozygous carriers (6.7%) of two different germ-line mutations of NBN gene; all of them had classic MB. Our results indicate that heterozygous carriers of the germ-line NBN gene mutations (c.511A>G and c.657_661del5) may exhibit increased susceptibility to developing MB. The risk of medulloblastoma is estimated to be 3.0 (for c.511A>G) and 4.86 (for c.657_661del5) times higher than in the general Polish population (p<0.05). These results suggest that heterozygous NBN germ-line mutations may contribute to the etiology of medulloblastoma.
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Affiliation(s)
- Elżbieta Ciara
- Department of Medical Genetics, The Children's Memorial Health Institute, Al. Dzieci Polskich 20, 04-730, Warsaw, Poland
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65
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von Hoff K, Hartmann W, von Bueren AO, Gerber NU, Grotzer MA, Pietsch T, Rutkowski S. Large cell/anaplastic medulloblastoma: outcome according to myc status, histopathological, and clinical risk factors. Pediatr Blood Cancer 2010; 54:369-76. [PMID: 19908297 DOI: 10.1002/pbc.22339] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
PURPOSE To evaluate the prognostic impact of large cell/anaplastic (LC/A) histology together with molecular and clinical risk factors in childhood medulloblastoma. METHODS Three consecutive prospective medulloblastoma trials were screened for patients with the histological diagnosis of LC/A medulloblastoma. Tumors were considered as LC/A if they displayed areas of severe cytological anaplasia or a significant or predominant large cell component. Histology was centrally confirmed. Genomic DNA amplification of c-myc and n-myc, and mRNA expression of c-myc and trkC were analyzed. RESULTS Twenty-eight patients with LC/A medulloblastoma with a median age of 6.1 years (1.4-16.5 years) and a median follow-up of 4.5 years were identified (5% of all medulloblastoma). Four-year event-free (EFS) and overall survival (OS) were 58% and 67%. Young age and metastases (n = 13, 4-year EFS 31% vs. 82% in 15 children >4 years and without metastases, P = 0.001), large cell histology (n = 9, 4-year EFS 22% vs. 75%, P = 0.005) and c-myc amplification (n = 9, 4-year EFS 22% vs. 89%, P < 0.0001) were negative prognostic factors. C-myc amplification was highly correlated with young age (P < 0.001), metastases (P = 0.002) and large cell histology (P = 0.007). Outcome of 12 patients with severely anaplastic tumors without these risk factors was not impaired (4-year EFS 86%). CONCLUSION In a subgroup of patients without clinical and molecular risk factors outcome was favorable despite severely anaplastic histology. In contrast, c-myc amplification and large-cell histology were associated with an inferior outcome. Intensified treatment strategies should be considered for children with LC/A medulloblastoma and these characteristics.
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Affiliation(s)
- Katja von Hoff
- Department of Pediatrics, University of Wuerzburg, Wuerzburg, Germany
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66
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Manor E, Bodner L, Kachko P, Kapelushnik J. Derivative (22)t(3;22)(q12;p11.1) in desmoplastic medulloblastoma. ACTA ACUST UNITED AC 2010; 196:175-8. [PMID: 20082855 DOI: 10.1016/j.cancergencyto.2009.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Accepted: 09/12/2009] [Indexed: 11/19/2022]
Abstract
Medulloblastoma is a malignant invasive embryonal tumor of the cerebellum, representing 15-30% of pediatric brain tumors. An i(17q) abnormality appears in 40% of medulloblastomas, and usually not as a sole aberration; however, cytogenetic data for medulloblastoma are limited. Cytogenetic work-up of tumors is an important tool for diagnosis and prognosis, and in some cases has led to the development of new therapeutic modalities. In the present case, cytogenetic analysis of a medulloblastoma revealed an unbalanced karyotype in all cells analyzed: 46,XY,der(22)t(3;22)(q12;p11.1). This sole unbalanced translocation led to partial trisomy of 3q. The significance of this finding and its role in the pathogenesis of medulloblastoma need further clarification.
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Affiliation(s)
- Esther Manor
- Genetics Institute, Soroka University Medical Center, Faculty of Health Sciences, Ben-Gurion University of the Negev, P.O. Box 151, Be'er Sheva, 84501 Israel.
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67
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Shalaby T, von Bueren AO, Hürlimann ML, Fiaschetti G, Castelletti D, Masayuki T, Nagasawa K, Arcaro A, Jelesarov I, Shin-ya K, Grotzer M. Disabling c-Myc in childhood medulloblastoma and atypical teratoid/rhabdoid tumor cells by the potent G-quadruplex interactive agent S2T1-6OTD. Mol Cancer Ther 2010; 9:167-79. [PMID: 20053783 DOI: 10.1158/1535-7163.mct-09-0586] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We investigated here the effects of S2T1-6OTD, a novel telomestatin derivative that is synthesized to target G-quadruplex-forming DNA sequences, on a representative panel of human medulloblastoma (MB) and atypical teratoid/rhabdoid (AT/RT) childhood brain cancer cell lines. S2T1-6OTD proved to be a potent c-Myc inhibitor through its high-affinity physical interaction with the G-quadruplex structure in the c-Myc promoter. Treatment with S2T1-6OTD reduced the mRNA and protein expressions of c-Myc and hTERT, which is transcriptionally regulated by c-Myc, and decreased the activities of both genes. In remarkable contrast to control cells, short-term (72-hour) treatment with S2T1-6OTD resulted in a dose- and time-dependent antiproliferative effect in all MB and AT/RT brain tumor cell lines tested (IC(50), 0.25-0.39 micromol/L). Under conditions where inhibition of both proliferation and c-Myc activity was observed, S2T1-6OTD treatment decreased the protein expression of the cell cycle activator cyclin-dependent kinase 2 and induced cell cycle arrest. Long-term treatment (5 weeks) with nontoxic concentrations of S2T1-6OTD resulted in a time-dependent (mainly c-Myc-dependent) telomere shortening. This was accompanied by cell growth arrest starting on day 28 followed by cell senescence and induction of apoptosis on day 35 in all of the five cell lines investigated. On in vivo animal testing, S2T1-6OTD may well represent a novel therapeutic strategy for childhood brain tumors.
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Affiliation(s)
- Tarek Shalaby
- Department of Oncology, University Children's Hospital Zurich, Zurich, Switzerland
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Adamson DC, Shi Q, Wortham M, Northcott PA, Di C, Duncan CG, Li J, McLendon RE, Bigner DD, Taylor MD, Yan H. OTX2 is critical for the maintenance and progression of Shh-independent medulloblastomas. Cancer Res 2009; 70:181-91. [PMID: 20028867 DOI: 10.1158/0008-5472.can-09-2331] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OTX2 is a developmentally regulated transcription factor involved in early morphogenesis of the central nervous system. This gene is amplified and overexpressed in medulloblastoma cell lines, but the nature and extent of its genetic alterations in primary tumors have not been evaluated. Analysis of a large cohort of primary medulloblastomas revealed frequent focal copy number gain of a region minimally containing OTX2 as a single gene. OTX2 copy number gain was restricted to tumor subtypes that did not express a molecular signature of Wnt or Shh pathway activation. FISH analysis revealed copy number gain in a subset of cells within medulloblastoma samples, suggesting a late event in tumor progression. Gain of OTX2 copy number was associated with the presence of anaplastic histologic features and shorter survival in medulloblastoma patients. In support of a functional role, ectopic OTX2 expression enhanced proliferation and tumorigenicity of immortalized primary cells, whereas OTX2 knockdown in medulloblastoma cells prolonged the survival of animals bearing xenograft tumors. Mechanistic investigations revealed upregulation of MYC as a potential mechanism whereby OTX2 promotes tumor progression. Our findings define OTX2 as an important oncogenic driver in medulloblastoma.
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Affiliation(s)
- David C Adamson
- Department of Surgery, The Pediatric Brain Tumor Foundation Institute, and The Preston Robert Tisch Brain Tumor Center at Duke, Duke University Medical Center, Veterans Affairs Medical Center, Durham, North Carolina 27710, USA
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69
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Pizer BL, Clifford SC. The potential impact of tumour biology on improved clinical practice for medulloblastoma: progress towards biologically driven clinical trials. Br J Neurosurg 2009; 23:364-75. [PMID: 19637007 DOI: 10.1080/02688690903121807] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Medulloblastoma is the most common malignant brain tumour of childhood and accounts for around 10% of all childhood cancer deaths. Despite recent improvements in survival rates, the delivery of individualised therapies based on disease-risk remains a major goal; intensified treatment for poor-risk disease, whilst reducing therapy for favourable-risk cases, with the overall aim of maximising survival whilst minimising late effects. Current clinical indices for the prediction of disease course are imprecise, however a series of molecular and histopathological biomarkers have been identified recently, which may allow a more accurate prediction of disease outcome (e.g., beta-catenin status as a favourable-risk marker, MYC gene amplification and large-cell histology as high-risk markers). Pan-European clinical trials being planned for medulloblastoma by the SIOP Brain tumour group will assess the stratification of patients using molecular and histological biomarkers, alongside clinical indices, to select favourable, standard and high-risk treatment groups. This selection will underpin two concurrent trials; PNET 5, which will test whether treatment can be reduced for a favourable-risk disease sub-group, with the aim of maintaining survival rates while reducing late-effects, and PNET 6, which will aim to improve survival rates in the standard-risk group. The implementation of these trials presents important new logistical challenges within routine practice, involving (i) the development of quality-controlled sample collection and handling systems across multiple treatment centres, including the mandatory ascertainment of fresh-frozen tumour material, and (ii) the delivery of standardised central biomarker analysis and histopathological review, within the approximately 30-day post-surgical window, prior to the selection and commencement of adjuvant therapy. Feasibility studies to establish these systems are underway across SIOP Europe national groups. Their success will require a coordinated approach by the entire multidisciplinary team, including neurosurgeons, oncologists and neuropathologists, with the common aim of facilitating targeted delivery of individualised risk-adapted therapies for children with medulloblastoma.
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Affiliation(s)
- Barry L Pizer
- Department of Paediatric Oncology, Alder Hey Children's Hospital, Liverpool, UK
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70
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Kagawa N, Maruno M, Suzuki T, Hashiba T, Hashimoto N, Izumoto S, Yoshimine T. Detection of genetic and chromosomal aberrations in medulloblastomas and primitive neuroectodermal tumors with DNA microarrays. Brain Tumor Pathol 2009; 23:41-7. [PMID: 18095118 DOI: 10.1007/s10014-006-0201-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2005] [Accepted: 01/18/2006] [Indexed: 01/09/2023]
Abstract
Medulloblastoma (MB) is the most frequent infratentorial malignant brain tumor in children. In contrast, primitive neuroectodermal tumor (PNET) is defined as a supratentorial malignant tumor generated from the cerebral hemisphere. These tumors have considerable histological overlap but have different clinical outcomes including overall survival period, recurrence rate, and chemosensitivity. We investigated the amplification and/or deletion of genes and the chromosomal gain and/or loss in 10 MBs and 3 PNETs with a genomic DNA microarray system. Genes that are frequently amplified in these both these tumors include MSH2, N-myc, AKT3, and EGFR. Amplifications of SNRPN, MYB, and PTEN are observed only in MB. The genes associated with Wnt/APC and Shh/PTCH pathways also have some aberrations. Common chromosomal aberrations include gains at 17q and 7q and losses at 17p. Minor chromosomal losses were also detected at 1p, 8p + q, 11p, 10p + q, 13q, 16q, and Xp + q in MB. SPNETs tend to contain fewer chromosomal and genetic abnormalities than MBs. In conclusion, there are gene expression and chromosomal differences between MBs and SPNETs. These differences may correlate with the prognosis.
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Affiliation(s)
- Naoki Kagawa
- Department of Neurosurgery, Osaka University Graduate School of Medicine, 2-2 Yamadaka, Suita, Osaka, 565-0871, Japan
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Mouse models of CNS embryonal tumors. Brain Tumor Pathol 2009; 26:43-50. [PMID: 19856214 DOI: 10.1007/s10014-009-0253-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2009] [Accepted: 05/01/2009] [Indexed: 01/26/2023]
Abstract
Central nervous system (CNS) embryonal tumors are devastating cancers in children, consisting of medulloblastomas, CNS primitive neuroectodermal tumors, and atypical teratoid/rhabdoid tumors. One of the reasons that CNS embryonal tumors remain difficult to treat is their rarity, which makes conducting clinical trials for these tumors difficult. Recent advances of molecular biology have led us to identify molecular and genetic causality of brain tumors. Based on the genetic alterations found in humans, multiple models of human CNS embryonal tumors have been generated in genetically engineered mice. These mouse models are valuable tools for understanding brain tumor biology and discovering novel therapeutic targets and drugs. In this article, we review molecular and cytogenetic characteristics of human CNS embryonal tumors and corresponding mouse models that have been developed. These findings indicate that common genetic abnormalities are seen in variants of human CNS embryonal tumors, and multiple histological variants of these tumors can be generated from a single set of genetic abnormalities in mice. These data provide insight into the biology and classification of CNS embryonal tumors.
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72
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Holthouse DJ, Dallas PB, Ford J, Fabian V, Murch AR, Watson M, Wong G, Bertram C, Egli S, Baker DL, Kees UR. Classic and desmoplastic medulloblastoma: Complete case reports and characterizations of two new cell lines. Neuropathology 2009; 29:398-409. [DOI: 10.1111/j.1440-1789.2008.00989.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Medulloblastomas: a correlative study of MIB-1 proliferation index along with expression of c-Myc, ERBB2, and anti-apoptotic proteins along with histological typing and clinical outcome. Childs Nerv Syst 2009; 25:825-35. [PMID: 19444455 DOI: 10.1007/s00381-009-0884-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2009] [Indexed: 10/20/2022]
Abstract
BACKGROUND Medulloblastoma (MB) is the most common pediatric brain tumor. It is however rare in adults. The genetic and protein expression profile of medulloblastoma is complex, which is worthwhile in terms of prognostication and development or selection of targeted therapy. AIMS AND OBJECTIVES The aims and objectives to correlate the MIB-1 proliferation index and protein expression profiles of c-Myc, ERBB2, and anti-apoptotic proteins (Bcl2 and Bcl-xL) in tumor cells with histological subtypes and clinical outcome. METHODS AND MATERIAL In 50 cases, histopathological subtyping was done, and protein expression profiling by immunohistochemical technique was performed by stains for MIB-1, Bcl2, Bcl-xL, c-Myc, and ERBB2 in 30 cases. The findings were correlated with histological types and patient's average follow-up data. RESULTS Histological subtypes were similar to that described in literatures. The average expression of Bcl2, Bcl-xL, MIB-1, c-Myc, and ERBB2 were as follows: 50.38%, 38.18%, 59.03%, 46.16%, and 59.62%, respectively. Bcl2 expression showed statistically significant correlation with progress-free survival (PFS) [p = 0.046], while ERBB2 and MIB-1 showed a trend of higher expression in progressive disease. The protein expression pattern did not correlate with histological subtypes. CONCLUSION Though Bcl-2, ERBB2, and MIB-1 LI came out to be potential markers of aggressive behavior, c-Myc did not correlate with PFS in MB.
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Behdad A, Perry A. Central nervous system primitive neuroectodermal tumors: a clinicopathologic and genetic study of 33 cases. Brain Pathol 2009; 20:441-50. [PMID: 19725831 DOI: 10.1111/j.1750-3639.2009.00314.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Central nervous system (CNS) primitive neuroectodermal tumors (PNETs) include supratentorial, brain stem, and spinal cord tumors with medulloblastoma-like histopathology. The prognostic impact of various pathologic and genetic features has not been thoroughly investigated. After re-diagnosis of three infantile cases as atypical teratoid/rhabdoid tumor (AT/RT), 33 remaining CNS PNETs were retrieved for clinicopathologic and fluorescence in situ hybridization studies. Anaplastic and/or large cell features were seen in 18 of 33 (55%) examples and survival was decreased in these patients (P = 0.036). MYCN or MYCC gene amplifications were noted in about half, with a trend towards decreased survival (P = 0.112). Polysomies of chromosomes 2 and 8 were each individually associated with decreased survival in children, with an even stronger association when combined (P = 0.013). Neither EWS gene rearrangements, nor AT/RT-like 22q deletions were encountered. We conclude that in CNS PNET: (i) routine application of INI1 immunohistochemistry helps rule out AT/RT, particularly in infants; (ii) MYC gene amplifications (especially MYCN) are common; (iii) involvement of CNS parenchyma by Ewing sarcoma/peripheral PNET is rare enough that EWS gene testing is not necessary unless significant dural involvement is present; and (iv) both anaplastic/large cell features and polysomies of 2 and 8 are associated with more aggressive clinical behavior.
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Affiliation(s)
- Amir Behdad
- Department of Pathology, Cedar Sinai Medical Center, Los Angeles, Calif, USA
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75
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Buccoliero AM, Castiglione F, Rossi Degl'Innocenti D, Franchi A, Paglierani M, Sanzo M, Cetica V, Giunti L, Sardi I, Genitori L, Taddei GL. Embryonal tumor with abundant neuropil and true rosettes: morphological, immunohistochemical, ultrastructural and molecular study of a case showing features of medulloepithelioma and areas of mesenchymal and epithelial differentiation. Neuropathology 2009; 30:84-91. [PMID: 19563506 DOI: 10.1111/j.1440-1789.2009.01040.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Embryonal tumors are a group of malignant neoplasms that most commonly affect the pediatric population. Embryonal tumor with abundant neuropil and true rosettes is a recently recognized rare tumor. It is composed of neurocytes and undifferentiated neuroepithelial cells arranged in clusters, cords and several types of rosettes in a prominent neuropil-rich background. We describe a new case of this tumor. The patient, a 24-month-old female infant, was referred to the Meyer Children's Hospital with a history of right brachio-crural deficit associated with occasional episodes of headache and vomiting. Computed tomography scan and MRI revealed a large bihemispheric mass. The patient underwent two consecutive surgeries. The resultant surgical resection of the tumor was macroscopically complete. The postoperative period was uneventful. On light microscopy the tumor showed a composite morphology: embryonal tumor with abundant neuropil and true rosettes (specimen from the first surgery); medulloepithelioma with mesenchymal and epithelial areas (specimen from the second surgery). The immunohistochemistry evidenced the heterogeneous (neuronal, mesenchymal and epithelial) immunoprofile of tumoral cells. By real-time polymerase chain reaction (RT-PCR), the PTEN gene expression in the tumor was lower than in the five non-neoplastic brain tissues used as control. Mutation analysis did not show any variation in INI-1 and PTEN sequence while P53 analysis showed the presence of homozygote P72R variation. Fluorescent in situ hybridization analysis showed polysomy of chromosome 2 while amplification of N-MYC was not detected. Owing to the rarity of embryonal tumor with abundant neuropil and true rosettes, each new case should be recorded to produce a better clinical, pathological and molecular characterization of this lesion.
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Jacobs JFM, Coulie PG, Figdor CG, Adema GJ, de Vries IJM, Hoogerbrugge PM. Targets for active immunotherapy against pediatric solid tumors. Cancer Immunol Immunother 2009; 58:831-41. [PMID: 19009292 PMCID: PMC11030767 DOI: 10.1007/s00262-008-0619-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Accepted: 10/22/2008] [Indexed: 02/06/2023]
Abstract
The potential role of antibodies and T lymphocytes in the eradication of cancer has been demonstrated in numerous animal models and clinical trials. In the last decennia new strategies have been developed for the use of tumor-specific T cells and antibodies in cancer therapy. Effective anti-tumor immunotherapy requires the identification of suitable target antigens. The expression of tumor-specific antigens has been extensively studied for most types of adult tumors. Pediatric patients should be excellent candidates for immunotherapy since their immune system is more potent and flexible as compared to that of adults. So far, these patients do not benefit enough from the progresses in cancer immunotherapy, and one of the reasons is the paucity of tumor-specific antigens identified on pediatric tumors. In this review we discuss the current status of cancer immunotherapy in children, focusing on the identification of tumor-specific antigens on pediatric solid tumors.
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Affiliation(s)
- J F M Jacobs
- Department of Pediatric Hemato-oncology, Radboud University Medical Centre Nijmegen, Nijmegen, The Netherlands.
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Huse JT, Holland EC. Genetically engineered mouse models of brain cancer and the promise of preclinical testing. Brain Pathol 2009; 19:132-43. [PMID: 19076778 PMCID: PMC2659383 DOI: 10.1111/j.1750-3639.2008.00234.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Recent improvements in the understanding of brain tumor biology have opened the door to a number of rational therapeutic strategies targeting distinct oncogenic pathways. The successful translation of such “designer drugs” to clinical application depends heavily on effective and expeditious screening methods in relevant disease models. By recapitulating both the underlying genetics and the characteristic tumor‐stroma microenvironment of brain cancer, genetically engineered mouse models (GEMMs) may offer distinct advantages over cell culture and xenograft systems in the preclinical testing of promising therapies. This review focuses on recently developed GEMMs for both glioma and medulloblastoma, and discusses their potential use in preclinical trials. Examples showcasing the use of GEMMs in the testing of molecularly targeted therapeutics are given, and relevant topics, such as stem cell biology, in vivo imaging technology and radiotherapy, are also addressed.
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Affiliation(s)
- Jason T Huse
- Department of Cancer Biology and Genetics, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
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78
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Abstract
Studying the early stages of cancer can provide important insight into the molecular basis of the disease. We identified a preneoplastic stage in the patched (ptc) mutant mouse, a model for the brain tumor medulloblastoma. Preneoplastic cells (PNCs) are found in most ptc mutants during early adulthood, but only 15% of these animals develop tumors. Although PNCs are found in mice that develop tumors, the ability of PNCs to give rise to tumors has never been demonstrated directly, and the fate of cells that do not form tumors remains unknown. Using genetic fate mapping and orthotopic transplantation, we provide definitive evidence that PNCs give rise to tumors, and show that the predominant fate of PNCs that do not form tumors is differentiation. Moreover, we show that N-myc, a gene commonly amplified in medulloblastoma, can dramatically alter the fate of PNCs, preventing differentiation and driving progression to tumors. Importantly, N-myc allows PNCs to grow independently of hedgehog signaling, making the resulting tumors resistant to hedgehog antagonists. These studies provide the first direct evidence that PNCs can give rise to tumors, and demonstrate that identification of genetic changes that promote tumor progression is critical for designing effective therapies for cancer.
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79
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Takei H, Nguyen Y, Mehta V, Chintagumpala M, Dauser RC, Adesina AM. Low-level copy gain versus amplification of myc oncogenes in medulloblastoma: utility in predicting prognosis and survival. Laboratory investigation. J Neurosurg Pediatr 2009; 3:61-5. [PMID: 19119907 DOI: 10.3171/2008.10.peds08105] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Medulloblastoma (MB) is a malignant embryonal tumor of the cerebellum. Amplification of c-myc or N-myc is infrequently identified and, when present, is often associated with the large cell/anaplastic (LC/A) phenotype. The frequency of low-level copy gain of myc oncogenes and its relationship to prognosis of MB has not been explored. METHODS Archival cases of MB were histologically reviewed and classified into 3 major subtypes: classic, nodular, and LC/A. Using quantitative real-time polymerase chain reaction (PCR), the authors analyzed 58 cases with a pure histological subtype for the copy number (CN) of myc (c-myc and N-myc) oncogenes. Cases with > 5-fold CN were further analyzed using the fluorescent in situ hybridization (FISH) assay. Kaplan-Meier survival analysis was performed. RESULTS A > 5-fold myc CN was noted in 5 (20.8%) of 24 LC/A, 1 (5.3%) of 19 classic, and 2 (13.3%) of 15 nodular subtypes. In a significant number of tumors (14 [56%] of 24 LC/A, 13 [68%] of 19 classic, and 10 [67%] of 15 nodular MBs) the CN was > 2-fold but < 5-fold. High-level amplification, defined as > 10-fold CN, was only seen in the LC/A subtype (5 cases), although moderate amplification (> 5-fold but < 10-fold) could be detected in other histological subtypes. Fluorescence in situ hybridization readily detected most cases corresponding to tumors with > 5-fold amplicon CN by quantitative real-time PCR, and could detect all 5 cases with > 10-fold CN by quantitative real-time PCR. The group of patients with > 5-fold myc amplicon CN showed significantly shorter survival than those with < 5-fold CN (p = 0.045), independent of histological subtype. CONCLUSIONS Since FISH could easily detect most cases in the moderate-to-high myc gene amplification (> 5-fold CN) group, the FISH assay has utility in detecting subsets of MB with poorer prognosis.
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Affiliation(s)
- Hidehiro Takei
- Department of Pathology, The Methodist Hospital, Texas Children's Cancer Center and Baylor College of Medicine, Houston, Texas 77030, USA.
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Abstract
Medulloblastoma is the most common brain tumor of childhood. Multiple signaling pathways have been associated with medulloblastoma formation and growth. These include the developmental pathways Hedgehog, (Hh) Notch, and Wnt as well as the receptor tyrosine kinases (RTK) c-Met, erbB2, IGF-R and TrkC, and the oncoprotein Myc. Here we review the involvement of these pathways in medulloblastoma malignancy with a focus on their mode of deregulation, prognostic value, functional effects, cellular and molecular mechanisms of action, and implications for therapy.
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Affiliation(s)
- Fadila Guessous
- Department of Neurology, University of Virginia, Charlottesville, Virginia 22908, USA
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81
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Kool M, Koster J, Bunt J, Hasselt NE, Lakeman A, van Sluis P, Troost D, Meeteren NSV, Caron HN, Cloos J, Mrsić A, Ylstra B, Grajkowska W, Hartmann W, Pietsch T, Ellison D, Clifford SC, Versteeg R. Integrated genomics identifies five medulloblastoma subtypes with distinct genetic profiles, pathway signatures and clinicopathological features. PLoS One 2008; 3:e3088. [PMID: 18769486 PMCID: PMC2518524 DOI: 10.1371/journal.pone.0003088] [Citation(s) in RCA: 524] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2008] [Accepted: 07/29/2008] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Medulloblastoma is the most common malignant brain tumor in children. Despite recent improvements in cure rates, prediction of disease outcome remains a major challenge and survivors suffer from serious therapy-related side-effects. Recent data showed that patients with WNT-activated tumors have a favorable prognosis, suggesting that these patients could be treated less intensively, thereby reducing the side-effects. This illustrates the potential benefits of a robust classification of medulloblastoma patients and a detailed knowledge of associated biological mechanisms. METHODS AND FINDINGS To get a better insight into the molecular biology of medulloblastoma we established mRNA expression profiles of 62 medulloblastomas and analyzed 52 of them also by comparative genomic hybridization (CGH) arrays. Five molecular subtypes were identified, characterized by WNT signaling (A; 9 cases), SHH signaling (B; 15 cases), expression of neuronal differentiation genes (C and D; 16 and 11 cases, respectively) or photoreceptor genes (D and E; both 11 cases). Mutations in beta-catenin were identified in all 9 type A tumors, but not in any other tumor. PTCH1 mutations were exclusively identified in type B tumors. CGH analysis identified several fully or partly subtype-specific chromosomal aberrations. Monosomy of chromosome 6 occurred only in type A tumors, loss of 9q mostly occurred in type B tumors, whereas chromosome 17 aberrations, most common in medulloblastoma, were strongly associated with type C or D tumors. Loss of the inactivated X-chromosome was highly specific for female cases of type C, D and E tumors. Gene expression levels faithfully reflected the chromosomal copy number changes. Clinicopathological features significantly different between the 5 subtypes included metastatic disease and age at diagnosis and histology. Metastatic disease at diagnosis was significantly associated with subtypes C and D and most strongly with subtype E. Patients below 3 yrs of age had type B, D, or E tumors. Type B included most desmoplastic cases. We validated and confirmed the molecular subtypes and their associated clinicopathological features with expression data from a second independent series of 46 medulloblastomas. CONCLUSIONS The new medulloblastoma classification presented in this study will greatly enhance the understanding of this heterogeneous disease. It will enable a better selection and evaluation of patients in clinical trials, and it will support the development of new molecular targeted therapies. Ultimately, our results may lead to more individualized therapies with improved cure rates and a better quality of life.
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Affiliation(s)
- Marcel Kool
- Department of Human Genetics, Academic Medical Center, Amsterdam, the Netherlands.
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Entz-Werle N, Carli ED, Ducassou S, Legrain M, Grill J, Dufour C. Medulloblastoma: what is the role of molecular genetics? Expert Rev Anticancer Ther 2008; 8:1169-81. [PMID: 18588461 DOI: 10.1586/14737140.8.7.1169] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Among pediatric malignancies, medulloblastoma (MB) is one of the most common malignant tumors of the CNS. In the past few years, thanks to a multidisciplinary approach including surgery, chemo- and radiation therapy, survival has significantly improved. Despite that, a third of patients still have a low chance of being cured and long-term survivors experience severe treatment-related sequelae. MBs are usually classified according to a clinical risk stratification, based on histological features, age at diagnosis, extent of tumor resection and presence or absence of metastases. However, these clinical variables have recently been reported to be poor for defining risk-related disease. Retrospective studies have identified histological or biological factors that have distinct roles in prognosis. As several pathways have been discovered to be involved in MB pathogenesis, they should be taken into account to more accurately stratify patients and their treatment and to develop innovative therapies.
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Affiliation(s)
- Natacha Entz-Werle
- Service de Pédiatrie, U 682 Inserm CHRU Hautepierre, Avenue Molière - 67098 Strasbourg Cedex France.
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83
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Behesti H, Marino S. Cerebellar granule cells: insights into proliferation, differentiation, and role in medulloblastoma pathogenesis. Int J Biochem Cell Biol 2008; 41:435-45. [PMID: 18755286 DOI: 10.1016/j.biocel.2008.06.017] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2008] [Revised: 05/30/2008] [Accepted: 06/09/2008] [Indexed: 12/28/2022]
Abstract
Cerebellar granule cells originate from precursors located in the dorsal region of rhombomere one within the hindbrain of developing embryos. They undergo proliferation for an extensive period well into postnatal stages of development to form the major cell type of the cerebellum, the most populous structure within the mammalian brain. Granule cell development is highly dependent upon the cerebellar environment and contact with neighbouring cells. In recent years, the molecular basis of these interactions has started to be unravelled. Granule cell precursors and the molecular mechanisms involved in controlling their proliferation have been shown to be involved in the pathogenesis of medulloblastoma, the most common malignant pediatric brain tumour. Here, we review the control of granule cell generation with emphasis on the molecular regulators of cell proliferation and differentiation during normal and malignant development.
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Affiliation(s)
- Hourinaz Behesti
- Institute of Cell and Molecular Science, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, 4 Newark Street, E1 2AT London, United Kingdom.
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84
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N-myc amplification was rarely detected by fluorescence in situ hybridization in retinoblastoma. Hum Pathol 2008; 39:1172-5. [DOI: 10.1016/j.humpath.2007.12.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Revised: 12/11/2007] [Accepted: 12/12/2007] [Indexed: 11/22/2022]
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85
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de Bont JM, Packer RJ, Michiels EM, den Boer ML, Pieters R. Biological background of pediatric medulloblastoma and ependymoma: a review from a translational research perspective. Neuro Oncol 2008; 10:1040-60. [PMID: 18676356 DOI: 10.1215/15228517-2008-059] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Survival rates of pediatric brain tumor patients have significantly improved over the years due to developments in diagnostic techniques, neurosurgery, chemotherapy, radiotherapy, and supportive care. However, brain tumors are still an important cause of cancer-related deaths in children. Prognosis is still highly dependent on clinical characteristics, such as the age of the patient, tumor type, stage, and localization, but increased knowledge about the genetic and biological features of these tumors is being obtained and might be useful to further improve outcome for these patients. It has become clear that the deregulation of signaling pathways essential in brain development, for example, sonic hedgehog (SHH), Wnt, and Notch pathways, plays an important role in pathogenesis and biological behavior, especially for medulloblastomas. More recently, data have become available about the cells of origin of brain tumors and the possible existence of brain tumor stem cells. Newly developed array-based techniques for studying gene expression, protein expression, copy number aberrations, and epigenetic events have led to the identification of other potentially important biological abnormalities in pediatric medulloblastomas and ependymomas.
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Affiliation(s)
- Judith M de Bont
- Department of Pediatric Oncology and Hematology, Erasmus MC-Sophia Children's Hospital, Rotterdam, The Netherlands.
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86
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de Haas T, Hasselt N, Troost D, Caron H, Popovic M, Zadravec-Zaletel L, Grajkowska W, Perek M, Osterheld MC, Ellison D, Baas F, Versteeg R, Kool M. Molecular risk stratification of medulloblastoma patients based on immunohistochemical analysis of MYC, LDHB, and CCNB1 expression. Clin Cancer Res 2008; 14:4154-60. [PMID: 18593994 DOI: 10.1158/1078-0432.ccr-07-4159] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Medulloblastoma is the most common malignant embryonal brain tumor in children. The current clinical risk stratification to select treatment modalities is not optimal because it does not identify the standard-risk patients with resistant disease or the unknown number of high-risk patients who might be overtreated with current protocols. The aim of this study is to improve the risk stratification of medulloblastoma patients by using the expression of multiple prognostic markers in combination with current clinical parameters. EXPERIMENTAL DESIGN Candidate prognostic markers were selected from literature or from medulloblastoma expression data. Selected genes were immunohistochemically analyzed for their prognostic value using medulloblastoma tissue arrays containing 124 well-characterized patient samples. RESULTS Protein expression analyses showed that the combined expression of three genes was able to predict survival in medulloblastoma patients. Low MYC expression identified medulloblastoma patients with a very good outcome. In contrast, concomitant expression of LDHB and CCNB1 characterized patients with a very poor outcome. Multivariate analyses showed that both expression of MYC and the LDHB/CCNB1 gene signature were strong prognostic markers independent of the clinical parameters metastasis and residual disease. Combined analysis of clinical and molecular markers enabled greater resolution of disease risk than clinical factors alone. CONCLUSIONS A molecular risk stratification model for medulloblastoma patients is proposed based on the signature of MYC, LDHB, and CCNB1 expression. Combined with clinical variables, the model may provide a more accurate basis for targeting therapy in children with this disease.
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Affiliation(s)
- Talitha de Haas
- Department of Human Genetics, Neuropathology, and Neurogenetics, Academic Medical Center, Amsterdam, the Netherlands
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87
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Martins RAP, Zindy F, Donovan S, Zhang J, Pounds S, Wey A, Knoepfler PS, Eisenman RN, Roussel MF, Dyer MA. N-myc coordinates retinal growth with eye size during mouse development. Genes Dev 2008; 22:179-93. [PMID: 18198336 DOI: 10.1101/gad.1608008] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Myc family members play crucial roles in regulating cell proliferation, size, differentiation, and survival during development. We found that N-myc is expressed in retinal progenitor cells, where it regulates proliferation in a cell-autonomous manner. In addition, N-myc coordinates the growth of the retina and eye. Specifically, the retinas of N-myc-deficient mice are hypocellular but are precisely proportioned to the size of the eye. N-myc represses the expression of the cyclin-dependent kinase inhibitor p27Kip1 but acts independently of cyclin D1, the major D-type cyclin in the developing mouse retina. Acute inactivation of N-myc leads to increased expression of p27Kip1, and simultaneous inactivation of p27Kip1 and N-myc rescues the hypocellular phenotype in N-myc-deficient retinas. N-myc is not required for retinal cell fate specification, differentiation, or survival. These data represent the first example of a role for a Myc family member in retinal development and the first characterization of a mouse model in which the hypocellular retina is properly proportioned to the other ocular structures. We propose that N-myc lies upstream of the cell cycle machinery in the developing mouse retina and thus coordinates the growth of both the retina and eye through extrinsic cues.
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Affiliation(s)
- Rodrigo A P Martins
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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88
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Abstract
Medulloblastoma is the most common embryonal tumour in children. Patients with medulloblastoma are currently staged as average-risk or poor-risk on the basis of clinical findings. With current multimodality therapy, nearly 90% of children with average-risk, non-disseminated medulloblastoma have 5-year event-free survival, and those with high-risk disease have a 60-65% survival rate; however, the outcome for younger children, particularly infants, is worse. Children who survive medulloblastoma are at risk of long-term sequelae related to the neurological effects of the tumour, surgery, or radiotherapy, and the additive effects of chemotherapy. Molecular biology has changed our understanding of medulloblastoma and has implications for diagnostic stratification and treatment. As newer biological agents are translated from the lab to the bedside, clinicians need to understand the fundamental signalling pathways that are targeted during therapy. Greater understanding of the molecular biology of medulloblastoma is needed so that more children can be cured or have an improved quality of life.
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89
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Functional and molecular interactions between the HGF/c-Met pathway and c-Myc in large-cell medulloblastoma. J Transl Med 2008; 88:98-111. [PMID: 18059365 DOI: 10.1038/labinvest.3700702] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The growth factor hepatocyte growth factor (HGF), also known as scatter factor, and its tyrosine kinase receptor c-Met play important roles in medulloblastoma malignancy. The transcription factor c-Myc is another contributor to the malignancy of these most common pediatric brain tumors. In the present study, we observed strong morphological similarities between medulloblastoma xenografts overexpressing HGF and medulloblastoma xenografts overexpressing c-Myc. We therefore hypothesized a biologically significant link between HGF/c-Met and c-Myc in medulloblastoma malignancy and studied the molecular and functional interactions between them. We found that HGF induces c-Myc mRNA and protein in established and primary medulloblastoma cells. HGF regulated c-Myc levels via transcriptional and post-transcriptional mechanisms as evidenced by HGF induction of c-Myc promoter activity and induction of c-Myc protein levels in the setting of inhibited transcription and translation. We also found that HGF induces cell cycle progression, cell proliferation, apoptosis and increase in cell size in a c-Myc-dependent manner. Activation of MAPK and PI3K, inhibition of GSK-3beta and translocation of beta-catenin to the nucleus as well as Tcf/Lef transcriptional activity were involved in mediating c-Myc induction by HGF. Induction of Cdk2 kinase activity was involved in mediating the cell cycle progression effects, and downregulation of Bcl-XL was involved in mediating the proapoptotic effects of HGF downstream of c-Myc. All molecules that mediated the effects of HGF on c-Myc expression, cell proliferation and apoptosis were expressed in human large-cell medulloblastoma tissues. We therefore established for the first time a functional cooperation between HGF/c-Met and c-Myc in human medulloblastoma and elucidated the molecular mechanisms of this cooperation. The findings provide a potential explanation for the high frequency of c-Myc overexpression in medulloblastoma and suggest a cooperative role for c-Met and c-Myc in large-cell anaplastic medulloblastoma formation.
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90
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Alvarez-Rodríguez R, Barzi M, Berenguer J, Pons S. Bone morphogenetic protein 2 opposes Shh-mediated proliferation in cerebellar granule cells through a TIEG-1-based regulation of Nmyc. J Biol Chem 2007; 282:37170-80. [PMID: 17951258 DOI: 10.1074/jbc.m705414200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nmyc is a potent regulator of cell cycle in cerebellar granular neuron precursors (CGNPs) and has been proposed to be the main effector of Shh (Sonic hedgehog) proliferative activity. Nmyc ectopic expression is sufficient to promote cell autonomous proliferation and can lead to tumorigenesis. Bone morphogenetic protein 2 (BMP2) antagonizes Shh proliferative effect by promoting cell cycle exit and differentiation in CGNPs. Here we report that BMP2 opposes Shh mitogenic activity by blocking Nmyc expression. We have identified TIEG-1 (KLF10) as the intermediary factor that blocks Nmyc expression through the occupancy of the Sp1 sites present in its promoter. We also demonstrate that TIEG-1 ectopic expression in CGNPs induces cell cycle arrest that can lead to apoptosis but fails to promote differentiation. Moreover, TIEG-1 synergizes with BMP2 activity to terminally differentiate CGNPs and independent differentiator signals such as dibutyryl cAMP and prevents apoptosis in TIEG-1 arrested cells. All together, these data strongly suggest that the BMP2 pathway triggers cell cycle exit and differentiation as two separated but coordinated processes, where TIEG-1 acts as a mediator of the cell cycle arrest.
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Affiliation(s)
- Rubén Alvarez-Rodríguez
- Department of Cell Death and Proliferation, Institute for Biomedical Research of Barcelona, IIBB-CSIC-IDIBAPS, 08036 Barcelona, Spain
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91
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Caracciolo V, Reiss K, Crozier-Fitzgerald C, De Pascali F, Macaluso M, Khalili K, Giordano A, Claudio PP. Interplay between the retinoblastoma related pRb2/p130 and E2F-4 and -5 in relation to JCV-TAg. J Cell Physiol 2007; 212:96-104. [PMID: 17385710 DOI: 10.1002/jcp.21005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Human polyomaviruses, which include JC virus (JCV) and BK virus (BKV), as well as the simian virus 40 (SV40), have been associated with human tumors and have been shown to be highly tumorigenic in experimental animal models. Although the mechanism by which JCV induces tumorigenesis is not entirely clear, earlier studies point to the involvement of the viral early protein T-antigen which has the ability to bind and inactivate tumor suppressors and cell cycle regulatory proteins, such as the retinoblastoma family proteins and p53. We investigated if the distribution between nucleus and cytoplasm of the transcription factors E2F4 and E2F5 is mediated by pRb2/p130 and if the presence of JCV T-antigen may impair this shuttling by sequestering pRb2/p130. The results showed that E2F4 was prevalently localized in the nucleus of both T-antigen positive and -negative R503 cells independently of the cell cycle phase. E2F5 instead was prevalently localized in the cytoplasmic fraction in G(0)/G(1), S-phase synchronized, and asynchronous R503 and R503 T-Ag positive cells. The presence of T-antigen did not influence the subcellular localization of these transcription factors E2F4 and E2F5, at least in this murine cellular model. Moreover, Small interference RNA experiments directed toward silencing the Rb2/p130 gene demonstrated that pRb2/p130 does not play a predominant role in the nuclear transportation of E2F4 and E2F5.
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Affiliation(s)
- Valentina Caracciolo
- Sbarro Institute for Cancer Research and Molecular Medicine, Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, Pennsylvania 19122, USA
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92
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Rutkowski S, von Bueren A, von Hoff K, Hartmann W, Shalaby T, Deinlein F, Warmuth-Metz M, Soerensen N, Emser A, Bode U, Mittler U, Urban C, Benesch M, Kortmann RD, Schlegel PG, Kuehl J, Pietsch T, Grotzer M. Prognostic relevance of clinical and biological risk factors in childhood medulloblastoma: results of patients treated in the prospective multicenter trial HIT'91. Clin Cancer Res 2007; 13:2651-7. [PMID: 17473196 DOI: 10.1158/1078-0432.ccr-06-1779] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To identify better risk stratification systems in childhood medulloblastoma based on clinical factors and analysis of routinely processed formalin-fixed tumor material. EXPERIMENTAL DESIGN Formalin-fixed paraffin-embedded tumor samples from well-documented patients treated within the prospective randomized multicenter trial HIT'91 were analyzed for DNA amplification of c-myc and N-myc (n=133) and mRNA expression of c-myc and trkC (n=104; compared with human cerebellum) using validated methods of quantitative PCR and reverse transcription-PCR. Results were related to clinical data and outcome. RESULTS TrkC and c-myc mRNA expression were identified as independent prognostic factors by multivariate analysis. Three risk groups were identified. (a) Favorable risk group: all 8 patients (2 metastatic) with high trkC (>1x human cerebellum) and low c-myc mRNA expression (<or=1x human cerebellum) remained relapse-free [7-year event-free survival (EFS), 100%]. (b) Poor risk group: 10 of 15 patients with metastatic disease and high c-myc and low trkC mRNA expression relapsed (7-year EFS, 33%). (c) Intermediate risk group: the 7-year EFS of the remaining 78 patients was 65%. Among 47 M(0) stage patients, all 10 patients with high trkC mRNA expression remained relapse-free compared with 15 events in 37 patients with low trkC mRNA expression levels (7-year EFS, 100% versus 62%; P=0.056). CONCLUSIONS Whereas the collection of fresh-frozen tumor samples remains a major challenge in large clinical trials, routinely processed paraffin-embedded tissue samples can be used to quantitate the prognostic biological markers trkC and c-myc. On prospective validation of cutoff levels, this may lead to improved stratification of treatment for children with medulloblastoma.
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Affiliation(s)
- Stefan Rutkowski
- University Children's Hospital of Wuerzburg, Wuerzburg, Germany.
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93
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Adesina AM, Nguyen Y, Mehta V, Takei H, Stangeby P, Crabtree S, Chintagumpala M, Gumerlock MK. FOXG1 dysregulation is a frequent event in medulloblastoma. J Neurooncol 2007; 85:111-22. [PMID: 17522785 DOI: 10.1007/s11060-007-9394-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Accepted: 04/17/2007] [Indexed: 01/10/2023]
Abstract
Medulloblastomas represent 20% of malignant brain tumors of childhood. Although, they show multiple, non-random genomic alterations, no common, early genetic event involving all histologic types of medulloblastomas have been described. Nineteen medulloblastomas were analyzed using chromosomal comparative genomic hybridization (cCGH). Nine tumors with the most frequent number of genetic changes were further analyzed using bacterial artificial chromosome array CGH (aCGH). With aCGH, the frequency of gains and losses were higher than with cCGH. Chromosome 2p gains spanning 2p11-2p25 including N-myc locus, 2p24.1 were detected in 5/9 (55%) tumors while 14q12 gains were detected in 6/9 (67%) tumors. The 14q12 locus overlapped with the FOXGI gene locus. Quantitative real time PCR showed a 2-7-fold copy gain for FOXG1 in all the nine tumors. Protein expression was demonstrated by immunohistochemistry in all histologic types. The expression of FOXG1 and p21cip1 showed an inverse relationship. FOXG1 copy gain (>2 to 21 folds) was seen in 93% (55/59) of a validating set of tumors and showed a positive correlation with protein expression (Spearman's rank order correlation coefficient = 0.276; P = 0.038) representing the first report of FOXG1 dysregulation in medulloblastoma. Modulation of FOXG1 expression in DAOY cell line using siRNA showed a modest decrease in proliferation with a 2-fold upregulation of p21cip1. Current reports indicate that FOXG1 represses TGF-beta induced expression of p21cip1 and cytostasis, and forms a transcriptional repressor complex with Notch signaling induced hes1. Our findings are consistent with a role for FOXG1 in the inhibition of TGF-beta induced cytostasis in medulloblastoma.
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Affiliation(s)
- Adekunle M Adesina
- Department of Pathology, Texas Children's Cancer Center, Baylor College of Medicine, One Baylor Plaza, Rm. 286A, Houston, TX 77030, USA.
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94
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Polkinghorn WR, Tarbell NJ. Medulloblastoma: tumorigenesis, current clinical paradigm, and efforts to improve risk stratification. ACTA ACUST UNITED AC 2007; 4:295-304. [PMID: 17464337 DOI: 10.1038/ncponc0794] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Accepted: 12/22/2006] [Indexed: 11/08/2022]
Abstract
Medulloblastoma is the most common brain malignancy in children and tremendous advances have recently been made in understanding the pathogenesis of this tumor. The Hedgehog and Wingless signaling pathways are implicated in medulloblastoma development, and both pathways were discovered as a result of analyses of genetic syndromes associated with the tumor. Over the past 80 years, considerable progress has been made in the treatment of what was once a fatal disease. The first survival reports followed the introduction of craniospinal irradiation, and yet the success of this modality, which continues to be a central component of treatment regimens for patients older than 3 years, comes at a significant cost. The present challenge in medulloblastoma treatment is to improve upon existing survival rates and to minimize the side effects of treatment. The current tools of clinical risk assessment fail to adequately identify patients older than 3 years who require less radiation and those who require more radiation. Significant effort has been made to improve clinical risk stratification and titration of treatment by analyzing properties of the tumor cells themselves for prognostic significance. These efforts include identifying histopathologic, cytogenetic, and molecular features that may correlate with prognosis.
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95
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Bayani J, Squire JA. Application and interpretation of FISH in biomarker studies. Cancer Lett 2007; 249:97-109. [PMID: 17287077 DOI: 10.1016/j.canlet.2006.12.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Accepted: 12/14/2006] [Indexed: 12/24/2022]
Abstract
Emerging genomic and proteomic data is creating new opportunities to identify novel biomarkers that will have pathway-specific therapeutic impact on cancer progression. Molecular cytogenetic and fluorescence in situ hybridization (FISH) methods have been primarily used in discovery genetic research laboratories until recently. New automated analytical platforms based on FISH technologies and tissue microarray methods are providing a rapid means to determine the impact of consistent genomic aberrations in clinical trials, and in studies designed to investigate differential chemotherapeutic response.
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Affiliation(s)
- Jane Bayani
- Division of Applied Molecular Oncology, Princess Margaret Hospital, University Health Network, 610 University Avenue, Room 9-717, Toronto, Ont., Canada M5G 2M9
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96
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Zindy F, Uziel T, Ayrault O, Calabrese C, Valentine M, Rehg JE, Gilbertson RJ, Sherr CJ, Roussel MF. Genetic Alterations in Mouse Medulloblastomas and Generation of TumorsDe novofrom Primary Cerebellar Granule Neuron Precursors. Cancer Res 2007; 67:2676-84. [PMID: 17363588 DOI: 10.1158/0008-5472.can-06-3418] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Mice lacking p53 and one or two alleles of the cyclin D-dependent kinase inhibitor p18(Ink4c) are prone to medulloblastoma development. The tumor frequency is increased by exposing postnatal animals to ionizing radiation at a time when their cerebella are developing. In irradiated mice engineered to express a floxed p53 allele and a Nestin-Cre transgene, tumor development can be restricted to the brain. Analysis of these animals indicated that inactivation of one or both Ink4c alleles did not affect the time of medulloblastoma onset but increased tumor invasiveness. All such tumors exhibited complete loss of function of the Patched 1 (Ptc1) gene encoding the receptor for sonic hedgehog, and many exhibited other recurrent genetic alterations, including trisomy of chromosome 6, amplification of N-Myc, modest increases in copy number of the Ccnd1 gene encoding cyclin D1, and other complex chromosomal rearrangements. In contrast, medulloblastomas arising in Ptc1(+/-) mice lacking one or both Ink4c alleles retained p53 function and exhibited only limited genomic instability. Nonetheless, complete inactivation of the wild-type Ptc1 allele was a universal event, and trisomy of chromosome 6 was again frequent. The enforced expression of N-Myc or cyclin D1 in primary cerebellar granule neuron precursors isolated from Ink4c(-/-), p53(-/-) mice enabled the cells to initiate medulloblastomas when injected back into the brains of immunocompromised recipient animals. These "engineered" tumors exhibited gene expression profiles indistinguishable from those of medulloblastomas that arose spontaneously. These results underscore the functional interplay between a network of specific genes that recurrently contribute to medulloblastoma formation.
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Affiliation(s)
- Frederique Zindy
- Department of Genetics, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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97
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Anti-proliferative activity of the quassinoid NBT-272 in childhood medulloblastoma cells. BMC Cancer 2007; 7:19. [PMID: 17254356 PMCID: PMC1794252 DOI: 10.1186/1471-2407-7-19] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Accepted: 01/25/2007] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND With current treatment strategies, nearly half of all medulloblastoma (MB) patients die from progressive tumors. Accordingly, the identification of novel therapeutic strategies remains a major goal. Deregulation of c-MYC is evident in numerous human cancers. In MB, over-expression of c-MYC has been shown to correlate with anaplasia and unfavorable prognosis. In neuroblastoma--an embryonal tumor with biological similarities to MB--the quassinoid NBT-272 has been demonstrated to inhibit cellular proliferation and to down-regulate c-MYC protein expression. METHODS To study MB cell responses to NBT-272 and their dependence on the level of c-MYC expression, DAOY (wild-type, empty vector transfected or c-MYC transfected), D341 (c-MYC amplification) and D425 (c-MYC amplification) human MB cells were used. The cells were treated with different concentrations of NBT-272 and the impact on cell proliferation, apoptosis and c-MYC expression was analyzed. RESULTS NBT-272 treatment resulted in a dose-dependent inhibition of cellular proliferation (IC50 in the range of 1.7-9.6 ng/ml) and in a dose-dependent increase in apoptotic cell death in all human MB cell lines tested. Treatment with NBT-272 resulted in up to 90% down-regulation of c-MYC protein, as demonstrated by Western blot analysis, and in a significant inhibition of c-MYC binding activity. Anti-proliferative effects were slightly more prominent in D341 and D425 human MB cells with c-MYC amplification and slightly more pronounced in c-MYC over-expressing DAOY cells compared to DAOY wild-type cells. Moreover, treatment of synchronized cells by NBT-272 induced a marked cell arrest at the G1/S boundary. CONCLUSION In human MB cells, NBT-272 treatment inhibits cellular proliferation at nanomolar concentrations, blocks cell cycle progression, induces apoptosis, and down-regulates the expression of the oncogene c-MYC. Thus, NBT-272 may represent a novel drug candidate to inhibit proliferation of human MB cells in vivo.
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98
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Min HS, Lee YJ, Park K, Cho BK, Park SH. Medulloblastoma: histopathologic and molecular markers of anaplasia and biologic behavior. Acta Neuropathol 2006; 112:13-20. [PMID: 16691420 DOI: 10.1007/s00401-006-0073-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2005] [Revised: 04/03/2006] [Accepted: 04/04/2006] [Indexed: 12/31/2022]
Abstract
Large cell/anaplastic (LC/A) medulloblastoma (MB) is a recently recognized variant of medulloblastoma known to be associated with an advanced stage and a poor prognosis. Although Eberhart et al. suggested histopathologic grading of medulloblastoma in 2002, no consensus has been reached in terms of determining the criteria of an LC/A variant, and its biological behavior continues to be the subject of debate. We retrospectively analyzed 74 cases (range 0.25-15 years) of MB clinicopathologically using the criteria established by Eberhart et al. The LC/A variant was identified in 16 cases (22% of MB cases), five of which showed a poor outcome. Most LC/A variant cases revealed synaptophysin immunoexpression (75%), but no epidermal growth factor receptor (EGFR) expression. Expression of synaptophysin, NeuN, GFAP, p53, c-erbB2, and EGFR did not differ in LC/A and non-LC/A variants. Seven of the 74 cases of medulloblastoma showed erbB2 amplification by FISH, four of which were LC/A variants. N-myc amplification was observed in only one LC/A variant, but no c-myc amplification was found. In patients younger than 10 years, the LC/A variant showed a significantly poorer outcome than the non-LC/A variant (P = 0.02), while no difference was found in older patients. Multivariate analysis revealed only metastasis on MRI and p53 expression, but not anaplasia as unfavorable prognostic factors. Our study suggests that prognostic implications of anaplasia in medulloblastoma are uncertain, and that the reproducibility of the histopathologic criteria of the LC/A variant should be reassessed before they can be applied in practical use.
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Affiliation(s)
- Hye Sook Min
- Department of Pathology, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul, 110-799, Korea
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99
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Abstract
In the past three decades, the survival for patients with medulloblastoma has improved remarkably. Contemporary "standard" therapy for children with medulloblastoma consists of maximal surgical resection followed by craniospinal irradiation with a boost to the posterior fossa, combined with adjuvant chemotherapy. The use of such multimodal therapeutic approaches results in progression-free survival (PFS) rates of 75% to 80% for patients with average-risk disease and approximately 60% for high-risk patients. However, despite the marked improvements in survival, many therapeutic challenges remain. Children with macroscopic metastatic disease (M2/M3) at presentation continue to fare poorly, with the best reports only attaining PFS rates up to 40%. Furthermore, despite intensive multimodal therapy, some patients have disease progression or recurrence, which for most remains incurable. The early recognition of these patients is imperative in order to institute treatment modifications, such as intensification and/or the use of novel experimental therapies. Additionally, the price for cure is clearly evident in survivors, who suffer from significant, often debilitating long-term neurocognitive and neuroendocrine sequela. Using the current clinical stratification system, a significant number of patients are overtreated and unnecessarily subjected to these long-term toxicities. This group of patients would benefit from reductions in therapy. Refinements in patient stratification and further improvement in outcome are unlikely to be achieved without improved knowledge of tumor biology. Several molecular alterations have already been identified, many of which appear to have prognostic significance. Furthermore, the disruption of molecular alterations in signaling pathways involved in the development and maintenance of medulloblastoma using novel molecularly targeted therapies promises to improve outcomes and reduce toxicity for patients with medulloblastoma. It is envisaged that in the near future children diagnosed with medulloblastoma will be more accurately stratified based on a combination of clinical variables and molecular profiles. Improved risk stratification will permit delivery of individualized therapy using conventional treatment modalities in conjunction with novel targeted therapeutic approaches.
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Affiliation(s)
- Nicholas G Gottardo
- Division of Neuro-oncology, Department of Hematology-Oncology, St. Jude Children's Research Hospital, 332 North Lauderdale Street, Memphis, TN 38105, USA
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100
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Abstract
The variable clinical outcomes of medulloblastoma patients have prompted a search for markers with which to tailor therapies to individuals. In this review, we discuss clinical, histological and molecular features that can be used in such treatment customization, focusing on how histopathological grading can impact both patient care and research on the molecular basis of CNS embryonal tumors. Medulloblastomas span a histological spectrum ending in overtly malignant large cell/anaplastic lesions characterized by increased nuclear size, marked cytological anaplasia, and increased mitotic and apoptotic rates. These "high-grade" lesions make up approximately one quarter of medulloblastomas, and recur and metastasize more frequently than tumors lacking anaplasia. We believe anaplastic change represents a type of malignant progression common to many medulloblastoma subtypes and to other CNS embryonal lesions as well. Correlation of these histological changes with the accumulation of genetic events suggests a model for the histological and molecular progression of medulloblastoma.
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Affiliation(s)
- Charles G Eberhart
- Department of Pathology, Division of Neuropathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2196, USA.
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