Submicroscopic deletions in 5q- associated malignancies.
OBJECTIVE
The deletion of the long arm of chromosome 5 is common in myelodysplastic syndromes (MDS) but is not limited to the 5q- syndrome as it is also seen in acute myeloid leukemia (AML), where it is often associated with other karyotypic aberrations. The aim of this study was to investigate whether deletions of known suppressor sequences occur in myeloid malignancies associated with 5q-.


METHODS
Thirty patients with MDS or AML were selected for the presence of a 5q karyotypic deletion, either isolated (19 cases) or associated with other chromosome changes (11 cases). Multiple fluorescent in situ hybridization (FISH) in interphase nuclei was applied in all cases using a panel of eleven probes for known suppressor genes or loci deleted in MDS/AML. Metaphase FISH was also performed to clarify discrepancies between conventional and molecular cytogenetics.


RESULTS
No additional deletions were found in nineteen cases with an isolated 5q-. Mono-allelic deletions where found in 9/11 cases, 3 of which were related to monosomies by conventional cytogenetics. Interphase-FISH showed p53, AML1, D13S25, NF1, or Ikaros in six out of nine (66%) patients with 5q- and additional karyotypic changes. Metaphase FISH was helpful in assigning some of these cryptic events to non-proliferating cells.


CONCLUSIONS
Our study emphasizes that isolated 5q- is the marker of a highly stable clone in both MDS and AML. AML with isolated 5q- are molecularly closer to 5q- syndrome than to AML with complex changes. Interphase-FISH data strongly support a mutator phenotype underlying complex karyotypes with a 5q deletion.
Crescenzi
Barbara
B
Hematology and Bone Marrow Trasplantation Unit, University of Perugia, Italy.
La Starza
Roberta
R
Romoli
Silvia
S
Beacci
Donatella
D
Matteucci
Caterina
C
Barba
Gianluca
G
Aventin
Ana
A
Marynen
Peter
P
Ciolli
Stefania
S
Nozzoli
Chiara
C
Martelli
Massimo Fabrizio
MF
Mecucci
Cristina
C
D000368:Aged; D020223:Chromosome Painting; D002895:Chromosomes, Human, Pair 5; D020732:Cytogenetic Analysis; D017353:Gene Deletion; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015470:Leukemia, Myeloid, Acute / Q000235:genetics*; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000235:genetics*