[FLT3 mutations in children with acute myeloid leukemia: a single center study].

OBJECTIVE

To study the clinical significance of FMS-like tyrosine kinase 3 (FLT3) mutations including internal tandem duplication (ITD) mutation and point mutation of tyrosine kinase domain (TKD) in children with acute myeloid leukemia (AML).

METHODS

Bone marrow samples from 116 children with newly-diagnosed AML were obtained. Gene mutations of FLT3/ITD and FLT3/TKD were detected by RT-PCR. The relationship of FLT3 gene mutations with the clinical characteristics and the therapeutic efficacy was observed.

RESULTS

FLT3/ITD and FLT3/TKD mutations were detected in 9 cases (7.8%) and 13 cases (11.2%) respectively out of the 116 children. FLT3/ITD mutations were observed in 3 cases of AML-M3 (3/9; 33.3%) and in 3 cases of AML-M5 (3/9; 33.3%). FLT3/TKD mutations were the most common in AML-M3 patients (10/13; 76.9%). The patients with FLT3/ITD mutations had a significantly higher peripheral WBC count and marrow blast percentage compared with the patients without FLT3/ITD mutations at diagnosis (P<0.01). The 3-year overall survival rate in patients with FLT3/ITD mutations was significantly lower than that in patients without FLT3/ITD mutations (38.9% vs 64.3%; P<0.05).

CONCLUSIONS

FLT3/TKD mutations are common in children with AML-M3. The AML children with FLT3/ITD mutations present a high peripheral WBC count and a high marrow blast percentage at diagnosis and have an unfavorable outcome.