title: Flow cytometric maturity score as a novel prognostic parameter in patients with acute myeloid leukemia.
abstract: The European LeukemiaNet (ELN) classification is widely accepted for risk stratification of patients with acute myeloid leukemia (AML). In order to establish immunophenotypic features that predict prognosis, the expression of single AML blast cell antigens has been evaluated with partly conflicting results; however, the influence of immunophenotypic blast maturity is largely unknown. In our study, 300 AML patients diagnosed at our institution between January 2003 and April 2012 were analyzed. A flow cytometric maturity score was developed in order to distinguish "mature" AML (AML-ma) from "immature" AML (AML-im) by quantitative expression levels of early progenitor cell antigens (CD34, CD117, and TdT). AML-ma showed significantly longer relapse-free survival (RFS) and overall survival (OS) than AML-im (p < 0.001). Interestingly, statistically significant differences in RFS and OS were maintained within the "intermediate-risk" group according to ELN (RFS, 7.0 years (AML-ma) vs. 3.3 years (AML-im); p = 0.002; OS, 5.1 years (AML-ma) vs. 3.0 years (AML-im); p = 0.022). Our novel flow cytometric score easily determines AML blast maturity and can predict clinical outcome. It remains to be clarified whether these results simply reflect an accumulation of favorable molecular phenotypes in the AML-ma subgroup or whether they rely on biological differences such as a higher proportion of leukemia stem cells and/or a higher degree of genetic instability within the AML-im subgroup.
authors.affiliation: Department of Hematology, Oncology and Tumor Immunology, Charité University Medicine, Campus Virchow-Klinikum, Berlin, Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Schneider
authors.forename: Anne
authors.initials: A
authors.lastname: Flörcken
authors.forename: Anju
authors.initials: A
authors.lastname: Singh
authors.forename: Seval
authors.initials: S
authors.lastname: Türkmen
authors.forename: Thomas
authors.initials: T
authors.lastname: Burmeister
authors.forename: Ioannis
authors.initials: I
authors.lastname: Anagnostopoulos
authors.forename: Antonio
authors.initials: A
authors.lastname: Pezzutto
authors.forename: Bernd
authors.initials: B
authors.lastname: Dörken
authors.forename: Jörg
authors.initials: J
authors.lastname: Westermann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000097:blood* / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D014411:Neoplastic Stem Cells / Q000378:metabolism; D011379:Prognosis; D055815:Young Adult