Analysis of FLT3 length mutations in 1003 patients with acute myeloid leukemia: correlation to cytogenetics, FAB subtype, and prognosis in the AMLCG study and usefulness as a marker for the detection of minimal residual disease

Blood. 2002 Jul 1;100(1):59-66. doi: 10.1182/blood.v100.1.59.

Abstract

FLT3 length mutation (FLT3-LM) is a molecular marker potentially useful for the characterization of acute myeloid leukemia (AML). To evaluate the distribution of FLT3-LM within biologic subgroups, we screened 1003 patients with AML at diagnosis for this mutation. FLT3-LM was found in 234 (23.5%) of all patients and thus is the most frequent mutation in AML described so far. Of all positive patients, 165 (70.5%) revealed a normal karyotype. Of the 69 patients with chromosome aberrations, 24 (34.8%) had a t(15;17). The mutation was rare in AML with t(8;21), inv(16) 11q23 rearrangements, and complex karyotypes. FLT3-LM was not distributed equally within different French-American-British (FAB) subtypes and was correlated with a high peripheral blood count in FAB M1, M2, and M4 (P <.0001). In addition, the median age of patients with the mutation was lower (54.9 vs 57.6 years; P =.043), and, at a ratio of 1.36:1 (P =.023), the mutation was more frequent in females than in males. Within the AMLCG study, FLT3-LM was of intermediate prognostic significance. The complete remission rate of 70.3% in patients with FLT3-LM was similar to that (70.4%) in patients without FLT3-LM. Overall survival was not different between patients with or without FLT3-LM. In contrast, patients with FLT3-LM had a significantly shorter event-free survival (7.4 vs 12.6 months; P =.0072) because of a higher relapse rate. Besides the importance of FLT3-LM for biologic and clinical characterization of AML, we show its value as a marker for disease monitoring based on 120 follow-up samples of 34 patients.

MeSH terms

  • Acute Disease
  • Biomarkers, Tumor / analysis
  • Biomarkers, Tumor / genetics
  • Chromosome Aberrations
  • Cohort Studies
  • Cytogenetic Analysis
  • DNA Mutational Analysis
  • Gene Frequency
  • Humans
  • Leukemia, Myeloid / classification
  • Leukemia, Myeloid / diagnosis
  • Leukemia, Myeloid / genetics*
  • Leukemia, Myeloid / mortality
  • Middle Aged
  • Mutation*
  • Neoplasm, Residual / diagnosis
  • Neoplasm, Residual / genetics
  • Neoplasm, Residual / mortality
  • Prognosis
  • Proto-Oncogene Proteins / genetics*
  • Receptor Protein-Tyrosine Kinases / genetics*
  • Survival Analysis
  • fms-Like Tyrosine Kinase 3

Substances

  • Biomarkers, Tumor
  • Proto-Oncogene Proteins
  • FLT3 protein, human
  • Receptor Protein-Tyrosine Kinases
  • fms-Like Tyrosine Kinase 3