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FLT3 internal tandem duplication mutations in adult acute myeloid leukaemia define a high-risk group
F M Abu-Duhier1, A C Goodeve, G A Wilson
1Division of Molecular and Genetic Medicine, Royal Hallamshire Hospital, Sheffield, UK.
Abstract:
Genomic DNA from 106 cases of adult de novo acute myeloid leukaemia (AML) was screened by polymerase chain reaction (PCR) and gel electrophoresis for FLT3 internal tandem duplication (ITD) mutations within the juxtamembrane (JM) domain. FLT3 mutations were detected in 14 cases (13.2%) and occurred in FAB types M1 (4 out of 14 cases), M3 (1 out of 10 cases), M4 (5 out of 37 cases) and M5 (4 out of 11 cases). Sequence analysis of four cases with abnormal PCR electrophoretic patterns revealed in frame duplications in the region of exon 11 of between 27 and 111 base pairs. Three are predicted to result in the tandem duplication of adjacent amino acid residues and one to result in a tandem duplication plus insertion of a novel amino acid motif. Statistical analysis showed the FLT3 mutations to be a strong prognostic factor, with patients lacking the mutation surviving significantly longer from diagnosis (mean 29.1 months) than those with an ITD (mean 12.8 months; P = 0.0002). Thirteen of the 14 patients with FLT3 mutations died within 18 months of diagnosis. FLT3 mutations were of prognostic significance in good risk disease (P = 0.04), as well as in patients with standard risk disease (P = 0.0096). This study demonstrates that the FLT3 ITD mutation occurs in a significant percentage of adult AML cases and is an important adverse prognostic factor that appears independent of conventional karyotypic findings.
Insights
FLT3 internal tandem duplication (ITD) mutations are found in 13.2% of adult acute myeloid leukemia (AML) cases. These FLT3 ITD mutations are a significant adverse prognostic factor, indicating shorter survival for AML patients.
Area of Science:
- Hematology
- Molecular Biology
- Oncology
Background:
- Adult de novo acute myeloid leukemia (AML) is a heterogeneous disease.
- Identifying prognostic markers is crucial for patient stratification and treatment decisions.
Purpose of the Study:
- To investigate the frequency and prognostic significance of FLT3 internal tandem duplication (ITD) mutations in adult AML.
- To analyze the impact of FLT3 ITD mutations on patient survival.
Main Methods:
- Genomic DNA screening of 106 adult AML cases using polymerase chain reaction (PCR) and gel electrophoresis.
- Sequence analysis for detailed characterization of identified mutations.
- Statistical analysis to assess prognostic value.
Main Results:
- FLT3 ITD mutations were detected in 14 out of 106 cases (13.2%).
- Mutations were observed across various FAB subtypes, including M1, M3, M4, and M5.
- Patients with FLT3 ITD mutations had significantly shorter survival (mean 12.8 months) compared to those without (mean 29.1 months).
- FLT3 mutations were a significant adverse prognostic factor in both good and standard risk disease categories.
Conclusions:
- FLT3 ITD mutations are present in a notable proportion of adult AML.
- The FLT3 ITD mutation is an important adverse prognostic factor, independent of karyotypic findings.
- Detection of FLT3 ITD mutations can aid in risk stratification for adult AML patients.