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Updated: Jul 10, 2026
Next Generation Sequencing for the Detection of Actionable Mutations in Solid and Liquid Tumors
Published on: September 20, 2016
[FLT3 internal tandem duplication in patients with acute promyelocytic leukemia]
Yong-mei Zhu1, Yuan-fang Liu, Su-jiang Zhang
1Department of Hematology, Shanghai Institute of Hematology, RuiJin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China.
Objective:
To analyze the mutation of FLT3 internal tandem duplication (FLT3-ITD) in bone marrow cells from patients with newly-diagnosed acute promyelocytic leukemia (APL).
Methods:
The mutation of FLT3-ITD in bone marrow mononuclear cells (MNCs) from 103 APL patients were screened by polymerase chain reaction (PCR) and the clinical features of ITD positive patients were analyzed.
Results:
FLT3-ITD mutations were identified in 19.4% (20/103) patients. It was associated with short/variant form of PML-RAR alpha isoforms (P < 0.0001). Among the 20 patients with FLT3-ITD mutation, 16 presented with short, 2 with variant and 2 with long form of PML-RAR alpha isoforms. Patients with FLT3-ITD mutation also presented significantly higher initial peripheral white blood cell count (WBC) (P < 0.01), especially in those with short/variant PML-RAR alpha isoforms (P = 0.015). For patients with long form PML-RAR alpha, there was no significant difference in initial WBC. Out of FLT3-ITD positive patients, 18/20 (90%) obtained complete remission and 16 evaluable patients (2 lost follow-up) remained in first remission in a median follow-up of 26 (11-47) months.
Conclusion:
FLT3-ITDs are frequently identified in patients with newly diagnosed APL. FLT3-ITD mutation is associated with short/variant form of PML-RAR alpha fusion gene and higher initial WBC. No significant impact on treatment outcome was observed with a limited follow-up.
Insights
FLT3-ITD mutations are common in acute promyelocytic leukemia (APL) and linked to specific PML-RAR alpha isoforms and higher white blood cell counts. This FLT3 mutation did not significantly impact treatment outcomes in this study.
Area of Science:
- Hematology
- Molecular Biology
- Oncology
Context:
- Acute promyelocytic leukemia (APL) is a distinct subtype of acute myeloid leukemia.
- FLT3 internal tandem duplication (FLT3-ITD) is a known genetic alteration in various leukemias.
- Understanding FLT3-ITD in APL is crucial for prognostication and treatment strategies.
Purpose:
- To investigate the frequency of FLT3-ITD mutations in newly-diagnosed APL patients.
- To analyze the correlation between FLT3-ITD mutations and clinical characteristics, including PML-RAR alpha isoforms and white blood cell (WBC) counts.
- To assess the impact of FLT3-ITD on treatment outcomes in APL.
Summary:
- FLT3-ITD mutations were detected in 19.4% of 103 newly-diagnosed APL patients.
- FLT3-ITD positivity was significantly associated with short/variant PML-RAR alpha isoforms and elevated initial WBC counts.
- Complete remission rates were high (90%) in FLT3-ITD positive patients, with sustained remission observed in most.
Impact:
- FLT3-ITD is a frequent finding in APL, associated with specific molecular and clinical features.
- The study suggests FLT3-ITD may not adversely affect short-term treatment outcomes in APL.
- Further long-term studies are needed to fully elucidate the prognostic significance of FLT3-ITD in APL.
