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del(20q) in myeloid malignancies

Identity

 
  del(20q) G- banding (left) - Courtesy Diane H. Norback, Eric B. Johnson, Sara Morrison-Delap UW Cytogenetic Services; R-banding (right) - Courtesy Hossein Mossafa (top), Jean-Luc Lai (middle); bottom: Jean Loup Huret.

Clinics and Pathology

Disease a very large spectrum of hematological malignancies as myelodysplastic syndromes (MDS), acute non lymphocytic leukemias (ANLL), polycythemia vera, chronic neutrophilic leukemia
Phenotype / cell stem origin as described in various types of hematological disorders, 20q- appears as a primary karyotypic abnormality occurring in a pluripotential hematopoietic stem cell; the pathogenic mechanism by which 20q- alters the hematopoietic stem cells in hematological disorders remains unknown; 20q- may confer a proliferative advantage to myeloid cells through deletion of a tumor suppressor gene
Epidemiology an interstitial or terminal deletion of the long arm of chromosome 20 (20q-) has been described as the second most frequent sole clonal structural abnormality (5 %) behind t(9.22)
Prognosis
  • in MDS, 20q- alone is associated with a good prognosis regarding survival and potential for AML evolution, as defined by the International Prognostic Scoring System (IPSS) for MDS prognosis
  • in de novo acute leukemia, a poor response to treatment and a reduced survival is observed
  • in myeloproliferative disorders, the presence of 20q does not appear to adversely affect survival
  • Cytogenetics

    Cytogenetics Morphological the breakpoint on chromosome 20 is not constant; 20q- is frequently associated with other cytogenetic abnormalities as del(5q), trisomy 8, trisomy 21, deletions or translocations involving the long arm of chromosome 13; a newly described translocation t(11;20)(p15;q11) resulting in a NUP98- TOP1 fusion gene was described in therapy-related myelodysplastic syndrome (RAEB); t(11;20)(p15;q11) is a rare recurrent translocation reported in patients with MDS, ANLL and polycythemia vera
    Cytogenetics Molecular a small fragment (around 8 Mb), proximally flanked by D20S206 and distally by D20S119 and UT 654 was identified using FISH
    Additional anomalies del(5q), trisomy 8, deletions or translocations involving 13q and trisomy 21

    Genes involved and Proteins

    Note genes remaining within this deleted region are topoisomerase 1 (TPO1-OMIN 126420), phospholipase C (PLC1), hepatocyte factor nuclear 4 (HNF4) and adenosine desaminase (ADA); recently, a new gene KRML transcriptional regulator was mapped in the smallest commonly deleted region in malignant myeloid leukemias

    Translocations implicated (Data extracted from papers in the Atlas)

     del(20q)

    External links

    Mitelman database Mitelman database (CGAP - NCBI)
    del(20q) - Mitelman database (CGAP - NCBI)

    Bibliography

    Report of the committee on chromosome changes in neoplasia.
    Mitelman F, Kaneko Y, Trent J
    Cytogenetic Cell Genet. 1991 ; 58 : 1053-1079.
     
    The prognostic significance of deletion of the long arm of chromosome 20 in myeloid disorders.
    Campbell LJ, Garson OM
    Leukemia : official journal of the Leukemia Society of America, Leukemia Research Fund, U.K. 1994 ; 8 (1) : 67-71.
    PMID 8289501
     
    Hematologic disorders associated with deletions of chromosome 20q: a clinicopathologic study of 107 patients.
    Kurtin PJ, Dewald GW, Shields DJ, Hanson CA
    American journal of clinical pathology. 1996 ; 106 (5) : 680-688.
    PMID 8929482
     
    International scoring system for evaluating prognosis in myelodysplastic syndromes.
    Greenberg P, Cox C, LeBeau MM, Fenaux P, Morel P, Sanz G, Sanz M, Vallespi T, Hamblin T, Oscier D, Ohyashiki K, Toyama K, Aul C, Mufti G, Bennett J
    Blood. 1997 ; 89 (6) : 2079-2088.
    PMID 9058730
     
    Refinement of the commonly deleted segment in myeloid leukemias with a del(20q).
    Wang PW, Iannantuoni K, Davis EM, Espinosa R 3rd, Stoffel M, Le Beau MM
    Genes, chromosomes & cancer. 1998 ; 21 (2) : 75-81.
    PMID 9491317
     
    The t(11;20)(p15;q11) chromosomal translocation associated with therapy-related myelodysplastic syndrome results in an NUP98-TOP1 fusion.
    Ahuja HG, Felix CA, Aplan PD
    Blood. 1999 ; 94 (9) : 3258-3261.
    PMID 10556215
     
    Human KRML (MAFB): cDNA cloning, genomic structure, and evaluation as a candidate tumor suppressor gene in myeloid leukemias.
    Wang PW, Eisenbart JD, Cordes SP, Barsh GS, Stoffel M, Le Beau MM
    Genomics. 1999 ; 59 (3) : 275-281.
    PMID 10444328
     
    REVIEW articlesautomatic search in PubMed
    Last year articlesautomatic search in PubMed

    Contributor(s)

    Written12-2000Chrystèle Bilhou-Nabera

    Citation

    This paper should be referenced as such :
    Bilhou-Nabera, C
    del(20q) in myeloid malignancies
    Atlas Genet Cytogenet Oncol Haematol. 2001;5(1):33-34.
    Free online version   Free pdf version   [Bibliographic record ]
    URL : http://AtlasGeneticsOncology.org/Anomalies/del20qID1040.html

    © Atlas of Genetics and Cytogenetics in Oncology and Haematology
    indexed on : Fri Aug 8 11:57:20 CEST 2014


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