FISH investigation of 5q and 7q deletions in MDS/AML reveals hidden translocations, insertions and fragmentations of the same chromosomes

• Published in: Leukemia research 1998-04, Vol.22 (4), p.303-312
• Main Authors: Lessard, Michel, Herry, Angèle, Berthou, Christian, Léglise, Marie Chantal, Abgrall, Jean-François, Morice, Patrick, Flandrin, Georges
• Format: Article
• Language: English
• Subjects: Acute Disease; Aged; Biological and medical sciences; Child; Chromosome Deletion; Chromosomes 5 and 7 long arm deletions; Chromosomes, Human, Pair 5 - genetics; Chromosomes, Human, Pair 7 - genetics; DNA Fragmentation; DNA Transposable Elements; Female; Fragmentation; Hematologic and hematopoietic diseases; Hidden translocations; Humans; In Situ Hybridization, Fluorescence; Insertions; Leukemia, Myeloid - genetics; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Male; MDS/AML; Medical sciences; Middle Aged; Myelodysplastic Syndromes - genetics; Translocation, Genetic
• ISSN: 0145-2126; 1873-5835
• DOI: 10.1016/S0145-2126(97)00172-0

We have studied, by fluorescence in situ hydridization (FISH), chromosomes 5 and 7 in a series of 11 cases with 5q deletion, as sole anomaly (four cases), or in association with 7q deletion (seven cases), in MDS/AML patients. We found that, in some cases, a part of the so-called ‘lost’ chromosome 5 and 7 material, was actually translocated. These translocations may be either end-arm or whole-arm, as well as small insertions. Chromosomes 5 or 7 may be broken in more than two segments, defining ‘fragmentation’, giving rise to marker chromosomes. FISH allowed the identification of small material insertion, which is totally unidentified by classical cytogenetics. Chromosome 5 and 7 translocations occur irrespectively of the ‘de novo’ or ‘secondary’ type of myelodysplastic syndrome (MDS)/acute myeloid leukaemia (AML) patients.