title: Clinical characteristics of hybrid leukemia: report of five cases.
abstract: We studied clinical and biological features of five cases of hybrid leukemia. Three of the five patients were classified as biphenotypic leukemia because of the coexpression of myeloid/B lymphoid markers in patients 1 (FAB M2) and 2 (FAB CMMoL) and myeloid/T lymphoid markers in patient 3 (FAB M4). Patient 4 was identified as bilineal-biphenotypic leukemia because acute myelogenous leukemia (AML) (FAB M4) and acute lymphoblastic leukemia (ALL) (FAB L1) coexisted and each population coexpressed myeloid and T lymphoid markers. Patient 5 was identified as bilineal leukemia due to the conversion from AML (FAB M1) to ALL (FAB L1) at an interval of 3 months. The Philadelphia (Ph1) chromosome was negative in all cases. A leukemic blast colony formation using cell line 5637 conditioned medium as a stimulator was obtained in all four patients examined. Three of the five patients had been suffering from so-called stem cell disorders such as aplastic anemia in patient 2, trilineage myelodysplasia in patient 4 and refractory anemia with excess of blasts in transformation in patient 5. The pre-existing impairment of pluripotent stem cell was probably the background of these hybrid leukemia. Hybrid leukemia appears to have an inferior prognosis: an AML-directed chemotherapy resulted in a low remission rate (2/5) with a short duration of relapse free survival (1/2) and an ALL-directed chemotherapy produced no remission (0/3). Chronological phenotypic analysis revealed that hybrid features of leukemic blasts disappeared at the time of relapse in patient 1 and progression to AML in patient 2. Monitoring of lineage-associated markers should be required for the management of hybrid leukemia.
authors.affiliation: First Department of International Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Akashi
authors.forename: M
authors.initials: M
authors.lastname: Harada
authors.forename: T
authors.initials: T
authors.lastname: Shibuya
authors.forename: E
authors.initials: E
authors.lastname: Morioka
authors.forename: T
authors.initials: T
authors.lastname: Okamura
authors.forename: Y
authors.initials: Y
authors.lastname: Asano
authors.forename: S
authors.initials: S
authors.lastname: Taniguchi
authors.forename: T
authors.initials: T
authors.lastname: Teshima
authors.forename: M
authors.initials: M
authors.lastname: Kikuchi
authors.forename: Y
authors.initials: Y
authors.lastname: Niho
mesh_terms: D000328:Adult; D000368:Aged; D000954:Antigens, Surface / Q000097:blood; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007124:Immunoenzyme Techniques; D007621:Karyotyping; D015470:Leukemia, Myeloid, Acute / Q000145:classification* / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000145:classification* / Q000188:drug therapy; D014410:Tumor Stem Cell Assay
chemical_list: D000954:Antigens, Surface