title: Prognostic significance of FLT3 ITD and D835 mutations in AML patients.
abstract: Both ITD and D835 mutations of the fms-like tyrosine kinase (FLT3) gene cause constitutive activation of the receptor, in the absence of ligand. We have examined a cohort of 91 patients, AML (80) and MDS (11), to determine the prevalence of these mutations and any correlations between the two mutations and disease prognosis. FLT3/ITD (ITD+) or D835 mutations (D835+) were not detected in MDS patients examined. However, 10% (8/80) and 7.5% (6/80) of AML patients were ITD+ and D835+, respectively. ITD+ patients have a higher rate of relapse than patients with wild-type (WT) FLT3. Median overall survival was 4.6 months (range 0.6-36.2) for ITD+ and 19.85 months (range 0.2-197.5) for WT patients (P=0.0066), and disease-free survival (DFS) was also worse for ITD+ patients than FLT3/WT patients (P=0.047). FLT3/ITD is also a significant prognostic marker for overall survival (OS) and DFS in patients in the standard karyotype group (P=0.0040, 0.0365, respectively). ITD is more prevalent in patients in the standard karyotype category (7/41, 17.1%) as compared to patients in the poor-risk category (1/32, 3.1%). Similar to ITD, D835 mutations were found to be more frequent in patients with standard-risk rather than poor-risk cytogenetic category. WBC count (mean 63.8 x 10(9)/l) was significantly higher in ITD+ patients than patients with D835 mutations (mean 34.8 x 10(9)/l) and WT patients (mean 26.4 x 10(9)/l) (P=0.004). D835 mutants did not appear to have a worse median OS or DFS compared with the WT group. We conclude that FLT3/ITD mutations may be an important prognostic marker in AML, especially in the standard/good risk karyotype groups, where it may allow risk-directed therapy.
authors.affiliation: Molecular Oncology Group, Department of Clinical Haematology, Manchester Royal Infirmary, UK.
authors.forename: Mohammad Hasan
authors.initials: MH
authors.lastname: Sheikhha
authors.forename: Abida
authors.initials: A
authors.lastname: Awan
authors.forename: Khalid
authors.initials: K
authors.lastname: Tobal
authors.forename: John Ahman
authors.initials: JA
authors.lastname: Liu Yin
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D015331:Cohort Studies; D004789:Enzyme Activation / Q000235:genetics; D005091:Exons / Q000235:genetics; D005260:Female; D006801:Humans; D007621:Karyotyping; D007951:Leukemia, Myeloid / Q000145:classification / Q000235:genetics* / Q000401:mortality; D007958:Leukocyte Count; D015993:Life Tables; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009190:Myelodysplastic Syndromes / Q000235:genetics* / Q000401:mortality; D009363:Neoplasm Proteins / Q000235:genetics*; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D012306:Risk; D016019:Survival Analysis; D020080:Tandem Repeat Sequences; D051941:fms-Like Tyrosine Kinase 3
chemical_list: D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; C497970:FLT3 protein, human; D020794:Receptor Protein-Tyrosine Kinases; D051941:fms-Like Tyrosine Kinase 3