der(5)t(5;7)(q11.2;p11.2): A new recurring abnormality in malignant myeloid disorders☆

Abstract Complete or partial monosomy for the long arm of chromosomes 5 and/or 7 is frequently observed in malignant cells from patients with a therapy-related myelodysplastic syndrome (t-MDS) or therapy-related acute nonlymphocytic leukemia (t-ANLL). Partial monosomy is usually the result of a chromosomal deletion; however, unbalanced translocations have also been observed. We have identified one such translocation in three patients who had either t-ANLL or a primary MDS. The genetic consequences of this translocation [−5,−7,+der(5)t(5;7)(q11.2;p11.2)] are partial monosomy for the long arm of chromosome 5 and complete monosomy for the long arm of chromosome 7. Thus, this rearrangement may represent a new, recurring abnormality that is associated with malignant myeloid disorders.