Detection of nucleophosmin and FMS-like tyrosine kinase-3 gene mutations in acute myeloid leukemia

Nucleophosmin gene mutations are frequently reported in acute myeloid leukemia [AML] patients with normal karyotype, which is also frequently associated with internal tandem duplication mutations in the FMS-like tyrosine kinase-3 gene. We sought to detect the nucleophosmin and FMS-like tyrosine kinase-3 [FLT3] internal tandem duplication [ITD] mutations among Iranian patients with AML and to assess the relationship between these mutations and the subtypes of the disease. Cross-sectional study of patients referred during 2007 through 2009. Bone marrow and peripheral blood samples of 131 AML patients were randomly collected at the time of diagnosis and prior to treatment and the DNA extracted. After amplifying the nucleophosmin and FLT3 gene regions, positive cases were screened by conformation-sensitive gel electrophoresis and agarose gel electrophoresis techniques. Of 131 patients, 23 [17.5%] [0.95% Cl=0.107-0.244] had nucleophosmin gene mutations. The highest frequency of such mutations was found among the subtypes of M4 [30.4%], M3 [21.7%] and M5 [17.4%]. There was a high frequency of these mutations in the M3 subtype as well as a high frequency of allele D in all subtypes. Also, 21 [16.0%] samples [0.95% CI=0.092-0.229] had FLT3/ITD mutation, of which 8 samples had mutant nucleophosmin [8 of 23, 35%], and another 13 samples had wild-type nucleophosmin gene [13 of 108, 12%]. There was a high degree of association between the occurrence of nucleophosmin and FLT3/ITD mutations [P=.012]. Our data showed a high frequency of NPM1 mutations in the monocytic subtypes of AML, as well as a high degree of association between the occurrence of NPM1 and FLT3/ITD mutations

Assesment of FLT3-gene mutations among children with acute leukemia

FLT3-gene mutations cause leukemic cells to proliferate uncontrollably and leads to a poor prognosis. The aim of this study was to explore appropriate at diagnostic molecular tests and to screen mutations that occur in patients with acute leukemia. In this basic study, 91 children with acute myeloid leukemia [AML] and acute lymphoid leukemia [ALL] were investigated for FLT3-gene mutations, including ITD mutation [Internal Tandem Duplication] and the point mutation that is coded by exon 17. ITD mutation in FLT3 receptor was analyzed by PCR [Polymerase chain reaction] in 11, 12 exons and 11 intron using designed primers. For analysis of point mutation of Exon 17 in FLT3 receptor gene, the genomic DNA of patient was amplified using the PCR. Resulted PCR products were studied by ECORV enzyme and restriction length polymorphism [RFLP]. In cases of positive ITD, the sequencing method was applied. Of 91 acute leukemia patients, ITD mutation was observed in 7 cases. Two of 91 patients had point mutation of D835. Distribution of ITD and point mutation of D835 mutation was not identical in FAB subtypes. FLT3-gene mutations are prevalent mutation in children with acute leukemia. So, it can be decided about the treatment after molecular diagnosis of this mutaions, independent of FAB classification and before the treatment get started

Key regulatory gene expression in erythroleukemia differentiation

The characteristics of cellular and molecular mechanisms associated with cell proliferation and differentiation is important to understand malignancy. In this report we characterise a leukemic model, D5A1, to study the action of differentiation agent, cellular events and gene expression of the selected transcription factors. Cells induced with 4 mM hexamethylene bisacetamide [HMBA] caused signs of erythroid differentiation [changes in morphology and size, haemoglobinisation] and cessation of proliferation including accumulation of cells in G0/G1. Treatment with HMBA caused a time-related decrease of tumorigenicity detectable by 48 hour. Northern-blotting showed induction of -amino levulinic acid synthase-erythroid [ALAS-E] mRNA at 48 hours and appeared in a strong level subsequently. C-myc [myelocytomatosis] and c-myb [myeloblastoma] mRNA levels decreased transiently in early hours returning to control values by 24 hour and decreased again. Stem cell leukaemia [SCL] and GATA-1 mRNA were markedly down regulated in early hours and then returned back. A later time point, upregulation of GATA-1 and SCL was relevant to maturation phenotype. These data provide a useful model to study the cellular and molecular events in leukomogenesis and action of differentiation therapy in leukaemia