Chromosome 20 deletions in myelodysplastic syndromes and Philadelphia-chromosome-negative myeloproliferative disorders: characterization by molecular cytogenetics of commonly deleted and retained regions.
Deletion of the long arm of chromosome 20 is a recurrent abnormality observed in myelodysplastic syndromes (MDS) and in Philadelphia-chromosome-negative myeloproliferative disorders (MPD). Our objective was to characterize the deletion size among 38 MDS and MPD patients using fluorescence in situ hybridization (FISH) with bacterial artificial chromosome (BAC) probes and to define commonly deleted and retained regions on chromosome 20. Patients were distributed in three groups according to the World Health Organization classification: MDS (22 patients), MPD (12 patients) and myelodysplastic/myeloproliferative diseases (four patients). FISH with centromeric, subtelomeric, and unique sequence probes was performed to characterize the deletion whereas its size was delineated using BAC clones. All 38 deletions were found to be interstitial. A commonly deleted region was identified for each of the three groups; it varied from 6.62 to 10.4 Mb and showed considerable overlapping. Two commonly retained regions (CRR), also showing overlapping, were identified in all three groups, one in the centromeric region, the other in the telomeric region. The deletion size is highly variable, with no apparent recurrent breakpoint. The deletion may result in the loss of one or several tumor suppressor genes but the target genes remain unknown. Loss of genes plays an important part in the myeloid leukemic process associated with del(20q). However, genes located in the retained chromosomal regions may also play a role in the oncogenetic mechanisms.
Douet-Guilbert
Nathalie
N
Laboratoire d'Histologie, Embryologie et Cytogénétique, Faculté de Médecine et des Sciences de la Santé, Université de Bretagne Occidentale, Brest, France.
Basinko
Audrey
A
Morel
Frédéric
F
Le Bris
Marie-Josée
MJ
Ugo
Valérie
V
Morice
Patrick
P
Berthou
Christian
C
De Braekeleer
Marc
M
D000368:Aged; D000369:Aged, 80 and over; D002871:Chromosome Banding; D002872:Chromosome Deletion; D022202:Chromosomes, Artificial, Bacterial; D002890:Chromosomes, Human, Pair 20 / Q000235:genetics / Q000648:ultrastructure*; D015331:Cohort Studies; D005260:Female; D017353:Gene Deletion; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D054438:Leukemia, Myeloid, Chronic, Atypical, BCR-ABL Negative / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000235:genetics*; D009196:Myeloproliferative Disorders / Q000235:genetics*; D010677:Philadelphia Chromosome