Redefining monosomy 5 by molecular cytogenetics in 23 patients with MDS/AML.

CHROMOSOMES; MYELODYSPLASTIC syndromes; MYELOID leukemia; HUMAN cytogenetics; KARYOTYPES; FLUORESCENCE in situ hybridization; CHROMOSOME abnormalities

Deletion of the long arm of chromosome 5 [del(5q)] or loss of a whole chromosome 5 (−5) is a common finding, arising de novo in 10% of patients with myelodysplastic syndromes (MDS) or acute myeloid leukemia (AML) and in 40% of patients with therapy-related MDS or AML. We investigated by molecular cytogenetics 23 MDS/AML patients for whom conventional cytogenetics detected a monosomy 5. Monosomy 5 was redefined as unbalanced or balanced translocation and ring of chromosome 5. Loss of 5q material was identified in all 23 patients, but one. One copy of EGR1(5q31) or CSF1R(5q33–34) genes was lost in 22 of the 23 patients. Chromosome 5p material was a constant chromosomal component of derivative chromosomes or rings in all patients, but one. Sequential fluorescent in situ hybridization studies with whole chromosome paints and region-specific probes, used as a complement to conventional cytogenetic analysis, allow a better interpretation of karyotypes in MDS/AML patients. [ABSTRACT FROM AUTHOR]