title: Prognostic significance of the FLT3 ITD mutation in patients with normal-karyotype acute myeloid leukemia in relapse.
abstract: BACKGROUND
  Fms-like tyrosine kinase 3 internal tandem duplication (FLT3 ITD) mutation is related to poor prognosis in normal-karyotype acute myeloid leukemia (AML). However, the prognostic significance of the mutation at relapse has not been adequately investigated. We investigated the prognostic significance of the FLT3 ITD mutation at relapse in normal-karyotype AML patients.
  
  
  METHODS
  We analyzed 69 normal-karyotype AML patients, in whom paired bone marrow samples taken at initial diagnosis and subsequent relapse were analyzed for the FLT3 ITD mutation at the Asan Medical Center between 1995 and 2009.
  
  
  RESULTS
  Forty patients showed a persistent wild-type genotype, 11 showed the FLT3 ITD mutation at diagnosis and relapse, and 9 lost and another 9 acquired the mutation at relapse. The mutation status at relapse affected the overall survival (OS), with the mutation group showing shorter OS and survival after relapse than the wild-type group did (P<0.001 and P<0.001, respectively), despite having received more frequent stem cell transplantation after relapse than the wild-type group did. However, no difference was detected in the OS and survival after relapse with regard to the mutation status at diagnosis.
  
  
  CONCLUSIONS
  The patients with FLT3 ITD mutation at relapse showed poorer prognoses than those without the mutation. However, mutation status at diagnosis did not affect the outcome. These results suggest that, in normal-karyotype AML patients with relapse, the prognostic significance of FLT3 ITD mutation at relapse is greater than that of the mutation status at diagnosis.
authors: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors: Sang Hyuk
authors: SH
authors: Park
authors: Hyun-Sook
authors: HS
authors: Chi
authors: Sook-Kyung
authors: SK
authors: Min
authors: Young-Uk
authors: YU
authors: Cho
authors: Seongsoo
authors: S
authors: Jang
authors: Chan-Jeoung
authors: CJ
authors: Park
authors: Jung-Hee
authors: JH
authors: Lee
authors: Je-Hwan
authors: JH
authors: Lee
authors: Kyoo-Hyung
authors: KH
authors: Lee
authors: Ho-Joon
authors: HJ
authors: Im
authors: Jong-Jin
authors: JJ
authors: Seo