[A study of NPM1 and FLT3 gene mutations in acute myeloid leukemia].
OBJECTIVE
To evaluate the prevalence and impact of NPM1 gene mutations and FLT3 internal tandem duplication (ITD) mutations in acute myeloid leukemia (AML).


METHODS
Mononuclear cells in bone marrow samples were collected from 86 adult patients with newly diagnosed AML. FLT3 and NPM1 genes were amplified with genomic DNA-PCR. NPM1 exon-12 mutations were evaluated with capillary electrophoresis and FLT3-ITD mutations were determined with agarose electrophoresis.


RESULTS
NPM1 gene mutations were identified in 29 of the 86 (33.7%) patients and FLT3-ITD in 15 of the 86 (17.4%) patients. In AML patients with normal karyotype, the frequencies of the two abnormalities were significantly higher than in those without (46.0% and 24.0%, P < 0.05). Both mutations were related to high peripheral white blood cell counts (P < 0.05). WBC counts in the six of the seven cases with NPM1+/FLT3-ITD+ AML were significantly higher (>50 x 10(9)/L). Compared with NPM1(-)AML patients, NPM1(+)AML patients were associated with lower expression of CD(34) (P < 0.001), higher complete remission (CR) rate after initial therapy (66.7% vs 53.3%, P > 0.05) and better overall survival (OS) (P > 0.05), but compared with FLT3-ITD(-)AML patients, FLT3-ITD+ AML patients were associated with lower CR rate (50.0% vs 58.8%; P > 0.05) and worse OS (P > 0.05). The CR rates were 66.7%, 62.5%, 50.0% and 42.9%, respectively, in NPM1+/FLT3-ITD(-), NPM1(-)/FLT3-ITD(-), NPM1+/FLT3-ITD+ and NPM1(-)/FLT3-ITD+AML groups (P > 0.05), but there was no significant differences in OS for four groups.


CONCLUSIONS
NPM1 and FLT3-ITD mutations are common in AML patients with normal karyotype and related with the clinical characteristics and prognosis of AML.
Wu
De-pei
DP
Department of Hematology, the First Affiliated Hospital of Soochow University, Jiangsu Institute of Hematology, Suzhou 215006, China. wudepei@medmail.com.cn
Yan
Ling-zhi
LZ
Yang
Li
L
Chen
Su-ning
SN
Wu
Xiao-jin
XJ
Liang
Jian-ying
JY
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005787:Gene Frequency; D006801:Humans; D007621:Karyotyping; D007951:Leukemia, Myeloid / Q000188:drug therapy / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009687:Nuclear Proteins / Q000235:genetics*; D000090243:Nucleophosmin; D011379:Prognosis; D016019:Survival Analysis; D051941:fms-Like Tyrosine Kinase 3 / Q000235:genetics*
C000716967:NPM1 protein, human; D009687:Nuclear Proteins; D000090243:Nucleophosmin; D051941:fms-Like Tyrosine Kinase 3