Nervous system: Medulloblastoma

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Written2000-07Anne Marie Capodano
Laboratoire de Cytogénétique Oncologique, Hpital de la Timone, 264 rue Saint Pierre, 13005 Marseille, France

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1. Identity

ICD-Morpho 9470/3 Medulloblastoma, NOS
Atlas_Id 5065
Phylum Central Nervous system::Medulloblastoma
WHO/OMS Classification Central Nervous system

2. Clinics and Pathology

Disease Medulloblastomas are malignant invasive embryonal tumours of the cerebellum with a tendency to metastasize in the central nervous system (CNS). This tumor is more frequently found in children.
Epidemiology It represents 10 at 20 % of brain tumours and 30 % of tumours localized in posterior fossa; annual incidence is 0,5 per 100 000 children; peak of occurrence at 7 years.
Histological features of a typical medulloblastoma: Homer-Wright rosettes - Anne Marie Capodano.
Pathology Belongs to the primitive neurectodermal tumours (PNET): highly malignant embryonal tumours of the CNS with predominant neuronal differentiation.
Several variants medulloblastoma are recognized in the OMS classification :
  • Classic medulloblastoma composed of densely jacked round-cells with round to oval hyperchromatic nuclei.
  • Desmoplastic medulloblastoma represents a variant with abundant reticulin and collagen.
  • Large cell medulloblastoma is a rare variant composed of cells with large round nuclei.
    Immuno histo chemistry : Classic medulloblastoma is strongly immuno-reactive for Vimentin. Some tumours are immunoreactive for NSE, Synaptophysine and GSAP.
  • Treatment The treatment associates total surgical resection and radiotherapy or, according to the age, chemotherapy.
    Prognosis Survival without recurrence is 50 at 70 %; depends on the quality of surgical resection and on the presence of metastases at the time of diagnosis.

    3. Cytogenetics

  • The most common specific abnormality in medulloblastomas, which is present in approximately 50 % of cases, is isochromosome 17q [i(17q)]. The breakpoint is in the proximal portion of p-arm at 17p11.2, so that the resultant structure is dicentric. In a few cases, partial or complete loss of 17p occurs through interstitial deletion, unbalanced translocation or monosomy 17.
  • Chromosome 1 is also involved in medulloblastomas. The most frequent abnormalities are unbalanced translocations, deletions and duplications. Rearrangements of chromosome 1 often result in trisomy 1q without loss of the p-arm.
  • Others less common chromosomal changes are: deletions of 6q, 9q, 10q, 11q, 11p and 16q, monosomy 22 and in rare cases double minutes.
  • i(17q) - R-banding.
    Cytogenetics Molecular
  • Isochromosome 17 q has been observed in interphase nuclei using fluorescence in situ hybridization. This technique is used in particular when only a few metaphases are obtained or when only normal diploid cells are obtained in culture.
  • 4. Genes involved and Proteins

  • Studies on loss of heterozygosity (LOH) have confirmed loss of portions of 17p in 30-45 % of cases. Some studies showed a correlation between LOH for 17p and a poor response to therapy and shortened survival. Mutations of p53 gene located on 17p13 have been found in only 5-10 % of these tumors.
  • Expression of PAX5 and PAX6 mRNA was shown in 70 % of medulloblastomas. The precise mechanism by which these genes are involved remains unknown.
  • Inactivation of PTCH tumor suppressor gene occurs in a subset of medulloblastomas.

  • 5. Bibliography

    Isochromosome 17q in primitive neuroectodermal tumors of the central nervous system.
    Biegel JA, Rorke LB, Packer RJ, Sutton LN, Schut L, Bonner K, Emanuel BS
    Genes, chromosomes & cancer. 1989 ; 1 (2) : 139-147.
    PMID 2487154
    Structural chromosomal abnormalities in human medulloblastoma.
    Bigner SH, Mark J, Friedman HS, Biegel JA, Bigner DD
    Cancer genetics and cytogenetics. 1988 ; 30 (1) : 91-101.
    PMID 3422050
    Cytogenetics and molecular genetics of malignant gliomas and medulloblastoma.
    Bigner SH, Vogelstein B
    Brain pathology (Zurich, Switzerland). 1990 ; 1 (1) : 12-18.
    PMID 1669688
    Differentiation in the medulloblastoma. A histological and immunohistochemical study.
    Burger PC, Grahmann FC, Bliestle A, Kleihues P
    Acta neuropathologica. 1987 ; 73 (2) : 115-123.
    PMID 3604579
    Deletion mapping of the medulloblastoma locus on chromosome 17p.
    Cogen PH, Daneshvar L, Metzger AK, Edwards MS
    Genomics. 1990 ; 8 (2) : 279-285.
    PMID 1979050
    Desmoplastic versus classic medulloblastoma: comparison of DNA content, histopathology and differentiation.
    Giangaspero F, Chieco P, Ceccarelli C, Lisignoli G, Pozzuoli R, Gambacorta M, Rossi G, Burger PC
    Virchows Archiv. A, Pathological anatomy and histopathology. 1991 ; 418 (3) : 207-214.
    PMID 1900966
    Molecular genetic studies of chromosome 11 and chromosome 22q DNA sequences in pediatric medulloblastomas.
    Lescop S, Lellouch-Tubiana A, Vassal G, Besnard-Guerin C
    Journal of neuro-oncology. 1999 ; 44 (2) : 119-127.
    PMID 10619495
    Diagnostic markers in paediatric medulloblastoma: a Paediatric Oncology Group Study.
    McLendon RE, Friedman HS, Fuchs HE, Kun LE, Bigner SH
    Histopathology. 1999 ; 34 (2) : 154-162.
    PMID 10064395
    Detection of an i(17q) chromosome by fluorescent in situ hybridization with a chromosome 17 alpha satellite DNA probe.
    Nakagawa H, Inazawa J, Misawa S, Tanaka S, Takashima T, Taniwaki M, Abe T, Kashima K
    Cancer genetics and cytogenetics. 1992 ; 62 (2) : 140-143.
    PMID 1394099
    Extensive genomic abnormalities in childhood medulloblastoma by comparative genomic hybridization.
    Reardon DA, Michalkiewicz E, Boyett JM, Sublett JE, Entrekin RE, Ragsdale ST, Valentine MB, Behm FG, Li H, Heideman RL, Kun LE, Shapiro DN, Look AT
    Cancer research. 1997 ; 57 (18) : 4042-4047.
    PMID 9307291
    Detection of i(17q) chromosome by fluorescent in situ hybridization (FISH) with interphase nuclei in medulloblastoma.
    Vagner-Capodano AM, Zattara-Cannoni H, Gambarelli D, Gentet JC, Genitori L, Lena G, Graziani N, Raybaud C, Choux M, Grisoli F
    Cancer genetics and cytogenetics. 1994 ; 78 (1) : 1-6.
    PMID 7987794
    Detection of 1q polysomy in interphase nuclei of human solid tumors with a biotinylated probe.
    Viegas-Péquignot E, Jeanpierre M, Dutrillaux AM, Gerbault-Seureau M, Muleris M, Dutrillaux B
    Human genetics. 1989 ; 81 (4) : 311-314.
    PMID 2539324

    6. Citation

    This paper should be referenced as such :
    Capodano, AM
    Nervous system tumors: Medulloblastoma
    Atlas Genet Cytogenet Oncol Haematol. 2000;4(3):147-148.
    Free journal version : [ pdf ]   [ DOI ]
    On line version :

    7. External links

    arrayMap Topo ( C71,C72) arrayMap ((UZH-SIB Zurich)   [auto + random 100 samples .. if exist ]   [tabulated segments]
    Other databaseTumor Portal - Broad Institute
    Other databasecBioPortal: Medulloblastoma (Broad, Nature 2012)
    Other databasecBioPortal: Medulloblastoma (ICGC, Nature 2012)
    Other databasecBioPortal: Medulloblastoma (PCGP, Nature 2012)
    Other databaseMedulloblastoma ( intOGen )
    Other databaseMedulloblastoma ( intOGen )
    Disease databaseNervous system: Medulloblastoma
    REVIEW articlesautomatic search in PubMed
    Last year articlesautomatic search in PubMed

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