11q23 rearrangement and duplication of MLLT1–MLL gene fusion in therapy-related acute myeloid leukemia

Abstract

Chromosomal aberrations involving 11q23 and disruption of the mixed lineage leukemia ( MLL ) gene have been frequently detected in diff erent forms of adult and childhood acute leukemia. MLL translocations generate an in-frame fusion gene, where the N-terminal portion of the MLL gene is fused to the C-terminal region of a partner gene, resulting in the generation of a chimeric protein with oncogenic properties. An 11q23 translocation is present in 7 – 10% of all cases of acute lymphoblastic leukemia (ALL), 5 – 8% of cases of acute myeloid leukemia (AML) and more than 50% of infants with acute leukemia regardless of lineage [1]. Abnormalities of 11q23 have also been reported in other hematologic malignant neoplasms such as therapy-related AML, biphenotypic acute leukemia, malignant lymphoma and myelodysplastic syndromes (MDS). Here, we report a case of therapy-related acute myeloid leukemia with an 11;19 translocation and duplication of the reciprocal MLLT1 – MLL fusion confi rmed by cytogenetic analysis,