title: Acute myeloid leukemia with biallelic CEBPA gene mutations and normal karyotype represents a distinct genetic entity associated with a favorable clinical outcome.
abstract: OBJECTIVE
  CEBPA mutations are found as either biallelic (biCEBPA) or monoallelic (moCEBPA). We set out to explore whether the kind of CEBPA mutation is of prognostic relevance in cytogenetically normal (CN) acute myeloid leukemia (AML).
  
  
  METHODS
  Four hundred sixty-seven homogeneously treated patients with CN-AML were subdivided into moCEBPA, biCEBPA, and wild-type (wt) CEBPA patients. The subgroups were analyzed for clinical parameters and for additional mutations in the NPM1, FLT3, and MLL genes. Furthermore, we obtained gene expression profiles using oligonucleotide microarrays.
  
  
  RESULTS
  Only patients with biCEBPA had an improved median overall survival when compared with patients with wtCEBPA (not reached v 20.4 months, respectively; P = .018), whereas patients with moCEBPA (20.9 months) and wtCEBPA had a similar outcome (P = .506). Multivariable analysis confirmed biCEBPA, but not moCEBPA, mutations as an independent favorable prognostic factor. Interestingly, biCEBPA mutations, compared with wtCEBPA, were never associated with mutated NPM1 (0% v 43%, respectively; P < .001) and rarely associated with FLT3 internal tandem duplication (ITD; 5% v 23%, respectively; P = .059), whereas patients with moCEBPA had a similar frequency of mutated NPM1 and a significantly higher association with FLT3-ITD compared with patients with wtCEBPA (44% v 23%, respectively; P = .037). Furthermore, patients with biCEBPA showed a homogeneous gene expression profile that was characterized by downregulation of HOX genes, whereas patients with moCEBPA showed greater heterogeneity in their gene expression profiles.
  
  
  CONCLUSIONS
  Biallelic disruption of the N and C terminus of CEBPA is required for the favorable clinical outcome of CEBPA-mutated patients and represents a distinct molecular subtype of CN-AML with a different frequency of associated gene mutations. These findings are of great significance for risk-adapted therapeutic strategies in AML.
authors.affiliation: Laboratory for Leukemia Diagnostics, Department of Internal Medicine III, University of Munich-Grosshadern, München, Germany.
authors.forename: Annika
authors.initials: A
authors.lastname: Dufour
authors.forename: Friederike
authors.initials: F
authors.lastname: Schneider
authors.forename: Klaus H
authors.initials: KH
authors.lastname: Metzeler
authors.forename: Eva
authors.initials: E
authors.lastname: Hoster
authors.forename: Stephanie
authors.initials: S
authors.lastname: Schneider
authors.forename: Evelyn
authors.initials: E
authors.lastname: Zellmeier
authors.forename: Tobias
authors.initials: T
authors.lastname: Benthaus
authors.forename: Maria-Cristina
authors.initials: MC
authors.lastname: Sauerland
authors.forename: Wolfgang E
authors.initials: WE
authors.lastname: Berdel
authors.forename: Thomas
authors.initials: T
authors.lastname: Büchner
authors.forename: Bernhard
authors.initials: B
authors.lastname: Wörmann
authors.forename: Jan
authors.initials: J
authors.lastname: Braess
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Hiddemann
authors.forename: Stefan K
authors.initials: SK
authors.lastname: Bohlander
authors.forename: Karsten
authors.initials: K
authors.lastname: Spiekermann
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D014408:Biomarkers, Tumor / Q000235:genetics*; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics*; D005260:Female; D020869:Gene Expression Profiling; D015973:Gene Expression Regulation, Leukemic; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D007621:Karyotyping; D015470:Leukemia, Myeloid, Acute / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D051788:Myeloid-Lymphoid Leukemia Protein / Q000235:genetics; D009367:Neoplasm Staging; D009687:Nuclear Proteins / Q000235:genetics; D000090243:Nucleophosmin; D020411:Oligonucleotide Array Sequence Analysis; D011379:Prognosis; D015996:Survival Rate; D016896:Treatment Outcome; D055815:Young Adult; D051941:fms-Like Tyrosine Kinase 3 / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D022762:CCAAT-Enhancer-Binding Proteins; C515848:CEBPA protein, human; C497422:KMT2A protein, human; C000716967:NPM1 protein, human; D009687:Nuclear Proteins; D000090243:Nucleophosmin; D051788:Myeloid-Lymphoid Leukemia Protein; D011495:Histone-Lysine N-Methyltransferase; C497970:FLT3 protein, human; D051941:fms-Like Tyrosine Kinase 3