Molecular cytogenetic characterization of acute myeloid leukemia and myelodysplastic syndromes with multiple chromosome rearrangements.

BACKGROUND AND OBJECTIVES Multiple chromosome rearrangements (MCRs) are found in 5-10% of newly diagnosed patients with acute myeloid leukemia (AML) and 15-30% of patients with myelodysplastic syndromes (MDS). However, the initial causes of MCRs and the molecular mechanisms involved are largely unresolved. Nor are the karyotypic patterns well studied, mainly because of the difficulties of obtaining complete karyotypes by G-banding. In this study, we applied spectral karyotyping (SKY) and comparative genomic hybridization (CGH) to investigate further the resulting chromosome imbalances and rearrangements in AML and MDS bone marrow cells with MCRs. DESIGN AND METHODS Bone marrow cells from 12 AML and 10 MDS patients with MCRs were collected at diagnosis and analyzed by G-banding, SKY and CGH. The patients' characteristics were also collected to pinpoint potential similarities and/or differences between the patients. RESULTS Our results show that some MCRs seen in AML are similar to MCRs seen in MDS. These MCRs often result in chromosome loss of 5q, 7q and 17p and gain of chromosome 8. INTERPRETATION AND CONCLUSIONS The characteristics associated with MRCs include old age, previous exposure to radio- and/or chemotherapy and a short survival time. Probably, these patients should be distinguished from AML patients with primary chromosome rearrangements among other unbalanced chromosome rearrangements. In our experience, SKY and CGH facilitated this process.