ABSTRACT
BACKGROUNDS: AML is an aggressive, phenotypically and genetically heterogenous clonal disease of hematopoietic progenitor cells with a great molecular variability. New WHO classification 2008 divides de novo AML according to cytogenetic and molecular prognostic and predictive markers. Recently, it is increasingly possible to identify a subgroup of poorer prognosis patients among those with normal karyotype AML. The aim of our study was to identify prognostically important molecular markers in children with AML, to stratify patients with normal karyotype and to monitor the disease according the genetic findings. MATERIAL AND METHODS: In 2008-2010, we analyzed bone marrow and peripheral blood samples of 20 children with de novo AML by conventional cytogenetic analysis, fluorescence in situ hybridisation and molecular diagnostics. The molecular analysis was performed on the cDNA level, with the restriction analysis of PCR products (FLT3-TKD), conventional PCR (MLL-PTD, NPM1mut, FLT3-ITD) and quantification RT-PCR method (expression of fusion transcripts, BAALC, WT1). RESULTS: Samples from 20 children with AML were analyzed using the conventional cytogenetics, FISH and molecular methods. Abnormal karyotype was identified in 13 patients (65%). Further analysis revealed FLT3-ITD in 5/20 (25%), FLT3-TKD in 3/20 (15%), NPM1mut in 2/20 (10%) and MLL-PTD in 1/20 (5%), overexpression of WT1 gene in 15/20 (75%) and overexpression of BAALC in 13/20 (65%) patients. CONCLUSION: Wide cytogenetic and molecular screening helped to find at least one genetic marker in all 20 patients for later follow-up and risk stratification. 4/20 (20%) patients died of the disease progression.
Subject(s)
Leukemia, Myeloid, Acute/genetics , Adolescent , Child , Child, Preschool , Cytogenetic Analysis , Female , Genes, Wilms Tumor , Humans , In Situ Hybridization, Fluorescence , Infant , Karyotyping , Male , Myeloid-Lymphoid Leukemia Protein/genetics , Neoplasm Proteins/genetics , Nuclear Proteins/genetics , Nucleophosmin , Polymerase Chain Reaction , Prognosis , fms-Like Tyrosine Kinase 3/geneticsABSTRACT
One of the most common chromosomal breakpoint regions in acute myeloid leukaemia is the chromosome band 11q23. The analysis of this region led to the discovery of the extremely promiscuous MLL gene, in which more than 60 MLL translocation partner genes have been described. Among the most frequent are t(9;11)(p21-22;q23)/MLL-AF9, t(10; 11)(p13; q23)/MLL-AF10, t(11;19)(q23;p13)/MLL-ELL, ENL and t(6;11)(q27;q23)/MLL-AF6. The presented work provides an overview of the molecular mechanisms by means of which MLL proto-oncogene can be converted into oncogene. Genetic alternations of the MLL Proto-Oncogene Protein besides translocation are also represented by complex chromosomal rearrangements, deletions, insertions, partial tandem duplications, amplifications and gains. These genetic alterations are described in the work from the diagnostic and prognostic point of view. Abnormalities of the MLL ProtoOncogene Protein are usually connected with bad prognosis. For that reason, in oncological practice, particular attention is paid to introducing new genetic methods for their identification. The above work gives well arranged information about different types of genetic tests and their outcomes, which can help oncologists in predicting the prognosis, in minimal residual disease monitoring and in modifying oncological patient treatment.
