Detection of NPM1 gene mutation in acute myeloid leukemia

Abstract

Objective To analyze the frequency of NPM1 mutation in de novo acute myeloid leukemia （AML） patients and the relationship between NPM1 mutation and chromosome alterations, as well as FAB subgroups, and to analyze the mutation type. Methods A total of 99 de novo AML patients from 2004 to 2010 in China-Japan Friendship Hospital were studied.Genomic DNA was amplified by polymerase chain reaction （PCR）, denaturing polyacrylamide gel electrophoresis （PAGE） and capillary electrophoresis were used to detect the mutation of NPM1 gene in 99 AML patients, and karyotyping was performed in 72 AML patients by G banding techniques.DNA sequences analysis of NPM1 mutation was performed on 10 patients.Chi-square test was used to compare the frequencies of NPM1 mutation among the different subgroups, and McNemar′s test was used to compare the different rates between denaturing PAGE and capillary electrophoresis. Results The frequencies of NPM1 mutations were detected in 15% (15/99) of AML patients with capillary electrophoresis and 11%(11/99) with denaturing PAGE(χ2=2.25，P>0.05).The NPM1 was at different rates in M2(27%, 8/30), M5(32%, 6/19), M6(13%, 1/8), respectively (χ2=1.06，P>0.05), and not detected in the other subgroups.NPM1 mutation in patients with normal karyotype(26%) was more prevalent than patients with abnormal karyotype(4%)(χ2=5.61，P<0.05).All of the 10 patients were of A type (c.860_863dupTCTG).The C-terminal portion of the NPM protein by replacing the last seven amino acids(WQWRKSL) with 11 residues (CLAVEEVSLRK).Two intronic deletions were novel, one case was IVS10-18_-15delCTTT, the other was IVS10-17_-15delTTT. Conclusions NPM1 mutations represents a common genetic abnormality in AML patients, and NPM1 mutation in patients with normal karyotype is higher than patients with abnormal karyotype.Two new intronic deletion mutations are identified.(Chin J Lab Med, 2012，35：27-31) Key words: Leukemia，myeloid，acute; Nuclear proteins; Mutation; Electrophoresis，capillary; Electrophoresis，polyacrylamide gel