title: The morphological subcategories of acute monocytic leukemia (M5a and M5b) share similar immunophenotypic and cytogenetic features and clinical outcomes.
abstract: Acute monocytic leukemia (M5) is a subtype of acute myeloid leukemia (AML) with two distinct morphologic subcategories, M5a and M5b. We compared the immunophenotype, cytogenetics and clinical outcome of AML M5 with non-M5 AML and also compared M5a with M5b. One hundred and twelve M5 (76 M5a, 36 M5b) and 726 non-M5 cases were identified and treated on protocols at our institution. There were no significant differences in immunophenotype between M5a and M5b. Translocation 11q23 was the sole abnormality in 18.6% of M5 and 3.2% of non-M5 (p<0.001). Trisomy 8 was also more prevalent in M5 (16.9%) than in non-M5 (8.7%; p=0.03). There was no significant difference in karyotypes between M5a and M5b. The complete remission rate was 70% for AML M5 and 57% for non-M5 AML (p=0.03). There was no significant difference in median overall survival or disease free survival for patients with M5 versus non-M5, M5a versus M5b. Our data indicate that the prognosis of AML M5 is similar to non-M5 AML and that M5a and M5b do not differ in immunophenotype, cytogenetics or clinical outcome.
authors: Department of Laboratory Hematology, University Health Network, University of Toronto, Toronto, Canada.
authors: Pierre
authors: P
authors: Villeneuve
authors: Dae Tong
authors: DT
authors: Kim
authors: Wei
authors: W
authors: Xu
authors: Joseph
authors: J
authors: Brandwein
authors: Hong
authors: H
authors: Chang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002869:Chromosome Aberrations; D020732:Cytogenetic Analysis; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D007621:Karyotyping; D007948:Leukemia, Monocytic, Acute / Q000188:drug therapy* / Q000235:genetics* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D016896:Treatment Outcome