title: Phenotypic conversion from t(8;21) acute myeloid leukemia to MLL gene rearrangement-positive acute lymphoblastic leukemia.
abstract: Phenotypic conversion from acute myeloid leukemia (AML) to acute lymphoblastic leukemia (ALL) is rare. A 38-year-old man was initially diagnosed as having AML (FAB-M2) associated with the t(8;21)(q22;q22) chromosomal abnormality. The blasts showed myeloperoxidase (MPO) activity and CD13 antigen expression. He showed complete remission after standard chemotherapy for AML. However, the patient relapsed with blasts showing ALL morphology (FAB-L1), MPO negativity, and CD19 antigen expression 33 months after cessation of AML therapy. Cytogenetic analysis at relapse was unsuccessful. Molecular analysis of ALL blasts revealed immunoglobulin heavy-chain gene and MLL gene rearrangements but no AML1 gene. MLL gene rearrangement or the 11q23 chromosomal abnormality has been associated with therapy-related leukemia. The subsequent ALL in our patient may have been induced by the chemotherapy including daunorubicin, known as a topoisomerase II inhibitor.
authors.affiliation: Department of Internal Medicine, Hitachi General Hospital, Ibaraki, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Ohsaka
authors.forename: K
authors.initials: K
authors.lastname: Kato
authors.forename: K
authors.initials: K
authors.lastname: Hikiji
mesh_terms: D000328:Adult; D002891:Chromosomes, Human, Pair 21 / Q000235:genetics*; D002898:Chromosomes, Human, Pair 8 / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D015321:Gene Rearrangement; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000235:genetics* / Q000276:immunology; D008297:Male; D051788:Myeloid-Lymphoid Leukemia Protein; D010641:Phenotype; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics*; D011519:Proto-Oncogenes; D014157:Transcription Factors; D014178:Translocation, Genetic
chemical_list: D004268:DNA-Binding Proteins; C497422:KMT2A protein, human; D014157:Transcription Factors; D051788:Myeloid-Lymphoid Leukemia Protein; D011495:Histone-Lysine N-Methyltransferase