[FLT3 internal tandem duplication in patients with acute promyelocytic leukemia].
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.


CONCLUSIONS
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.
Zhu
Yong-mei
YM
Department of Hematology, Shanghai Institute of Hematology, RuiJin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China.
Liu
Yuan-fang
YF
Zhang
Su-jiang
SJ
Shen
Zhi-xiang
ZX
Hu
Jiong
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D020080:Tandem Repeat Sequences; D051941:fms-Like Tyrosine Kinase 3 / Q000235:genetics*
C497970:FLT3 protein, human; D051941:fms-Like Tyrosine Kinase 3