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Significance of MLL gene aberrations in patients with acute myeloid leukemia
Šárová, Iveta ; Březinová, Jana (advisor) ; Král, Jiří (referee)
4 ABSTRACT Significance of MLL gene aberrations in patients with acute myeloid leukemia In acute myeloid leukemia (AML), predominantly in AML M5a, the most frequent recurrent aberration of chromosome 11 involves region 11q23. Molecular breakpoint studies of several translocations involving chromosomal band 11q23 led to the detection of a gene that was named MLL (myeloid/lymphoid leukemia). Since that time, more than 70 different translocation partners of the MLL gene have been described. This gene is important for the proper HOX gene expression during ontogenesis and hematopoiesis. Chromosomal aberrations affecting the MLL gene occur in 5 - 10 % of AML cases and are very variable. Aberrations of the MLL gene are associated with an aggresive type of the disease and its detection is needed for the treatment decision. Therefore, we investigated the occurrence of MLL abnormalities in bone marrow cells of the 66 newly diagnosed AML patients, using conventional cytogenetic and fluorescence in situ hybridization (FISH) analyses with a commercially available MLL Break Apart Rearrangement probe (Abbott VYSIS). Out of the 66 patients, we proved MLL abnormalities in 9 (13,6%): 5 (7,6%) showed translocation of MLL gene, in 3 (4,5%) we detected MLL gene amplification without any evidence of rearrangement and in 1 (1,5%)...
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The study of genetic changes of children patients suffering from the acute lymphoblastic leukemia (ALL) using mFISH / mBAND and micro-arrays.
Bártů, Linda ; Zemanová, Zuzana (advisor) ; Březinová, Jana (referee)
Acute lymphoblastic leukemia is the most common malignancy in children. The most important examination at the time of diagnosis includes karyotype of leukemic cells which divides patients into prognostic groups according to cytogenetic finding. In up to 90 % of patients the chromosomal aberrations with well known clinical significance are designated. One of cytogenetic type is high hyperdiploid ALL (51-68 chromosomes) associated with favorable prognosis. Nevertheless, relapses of the disease occur even in these children. One possible reason why this happens could be an increased genomic instability of leukemic cells that causes cryptic structural rearrangements. In a retrospective study, we examined a total of 232 children with newly diagnosed B-ALL using conventional cytogenetic analyses and interphase fluorescence in situ hybridization (I-FISH) with a panel of DNA probes (Abbott Vysis) in order to detect heteroploid cells. In patients with suspect cryptic structural chromosome aberrations, we analyzed the karyotypes in detail by multicolor FISH and multicolor banding (mFISH/mBAND; MetaSystems). The extent of aberrations was determined by comparative genomic hybridization on BAC arrays (array CGH; BlueGnome). Cell clones with high hyperdiploid karyotype were detected in a total of 102 children (44 %). In...
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Analysis of structural chromosomal rearrangements in hematological neoplasias; Study of structural chromosomal rearrangements of cells of chronic lymphocytic leukemia after DSP30/IL2 stimulated cultivation
Hrubá, Martina ; Michalová, Kyra (advisor) ; Goetz, Petr (referee) ; Březinová, Jana (referee)
Cytogenetic analysis of cells of chronic lymphocytic leukemia (CLL) is difficult because of their low proliferative activity. To obtain sufficient number of mitoses for performing chromosomal analysis a suitable stimulation of cell division is needed. Using DSP30/IL2 stimulated cultivation 391 CLL samples were investigated in 5 years' period. The cultivation was showed to have high success rate (96%; 375/391) with also high rate of detection of pathological clones by both karyotype and metaphase FISH analyses (in 84% of samples; 329/391). Almost in half of samples (44%; 171/391) other aberrations than recurrent FISH (i.e. 13q14 deletion, trisomy 12, TP53, ATM genes deletions) were found. Also high frequency of translocations (37%; 144/391), complex karyotypes (28%; 111/391) and clonal evolution, which was detected in one third of all samples (34% of samples with presence of more than two clones; 133/391) and like a new event in disease duration even more frequently (in 39% of samples repeatedly investigated after stimulated cultivation; 21/54), was revealed. The presence of translocations, complex karyotypes and clonal evolution was associated with progressive form of disease (P 0,000003, resp. P 0,0002 and P 0,05/P 0,04). In cases of the recurrent deletions the detailed analysis of metaphase...
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Frequency and significance of genetic changes in the genome of leukemia cells in children with T-ALL
Sládková, Lucie ; Zemanová, Zuzana (advisor) ; Březinová, Jana (referee)
T-ALL (T-cell acute lymphoblastic leukemia) is identified in 10-15 % cases of pediatric acute lymphoblastic leukemia and it is a clinically and genetically heterogeneous disease. About 50 % of patients have normal karyotype and although a number of cryptic recurrent chromosome aberrations have been reported their prognostic significance is not entirely clear. The aim of the study was to analyze bone marrow cells of children with T-ALL using cytogenomic methods to determine the frequency of cryptic aberrations and to assess their importance for disease prognosis. We examined diagnostic samples of 67 children with T-ALL (19 girls and 48 boys, median age 8 years). We analyzed the changes by G- banding, I-FISH (Dako, Abbott) and MLPA (MRC-Holland) methods. We detected cryptic aberrations in 60 children (91 %). The most frequent changes were deletions of the CDKN2A gene (48×) which were usually observed in combination with other changes and aberrations of loci for TCR genes (20×). TLX3 gene rearrangements were detected in 18 cases and were never associated with rearrangements of TCR loci. Complex karyotype was detected in 10 patients with recurrent breakpoints 5q35 and 10q24. 45 patients live in the first or second complete remission, relapse occurred in 14 children and 20 died. Statistical analysis of...
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Molecular-cytogenetic analysis of chromosome 11 aberrations in hematological malignancies
Šárová, Iveta ; Březinová, Jana (advisor) ; Goetz, Petr (referee) ; Jarošová, Marie (referee)
Chromosome 11 abnormalities are found in many hematological malignancies. In acute myeloid leukemia (AML), a proto-oncogene MLL (11q23.3) is frequently altered. However, rearrangements to other regions of chromosome 11 have been reported. Therefore, we have identified and characterized the chromosome 11 breakpoints and common deleted and amplified areas in the bone marrow or peripheral blood cells of newly diagnosed patients with AML. Many recurrent and random chromosome 11 breakpoints were identified (recurrent in bands 11p15.4 (in NUP98 gene), 11q23.3 (in the MLL gene), 11p13, 11p12 and 11q13.2) and deleted or duplicated/amplified regions were determined. We notified new possibly significant genes in the development of AML. Contrary to the MLL rearrangements, patients with other chromosome 11 changes were older, with complex karyotype, unbalanced aberrations and short survival. FISH screening was proved very helpful in case of deviding cells lack and cryptic MLL gene rearrangement. In conclusion, molecular analyses of chromosomal breakpoints and amplified or deleted areas are very important not only for the patient stratification into specific prognostic and clinical subgroups but also for the identification of genes involved in tumour pathogenesis. Further investigation of the affected genes and...
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Analysis of structural chromosomal rearrangements in hematological neoplasias; Study of structural chromosomal rearrangements of cells of chronic lymphocytic leukemia after DSP30/IL2 stimulated cultivation
Hrubá, Martina ; Michalová, Kyra (advisor) ; Goetz, Petr (referee) ; Březinová, Jana (referee)
Cytogenetic analysis of cells of chronic lymphocytic leukemia (CLL) is difficult because of their low proliferative activity. To obtain sufficient number of mitoses for performing chromosomal analysis a suitable stimulation of cell division is needed. Using DSP30/IL2 stimulated cultivation 391 CLL samples were investigated in 5 years' period. The cultivation was showed to have high success rate (96%; 375/391) with also high rate of detection of pathological clones by both karyotype and metaphase FISH analyses (in 84% of samples; 329/391). Almost in half of samples (44%; 171/391) other aberrations than recurrent FISH (i.e. 13q14 deletion, trisomy 12, TP53, ATM genes deletions) were found. Also high frequency of translocations (37%; 144/391), complex karyotypes (28%; 111/391) and clonal evolution, which was detected in one third of all samples (34% of samples with presence of more than two clones; 133/391) and like a new event in disease duration even more frequently (in 39% of samples repeatedly investigated after stimulated cultivation; 21/54), was revealed. The presence of translocations, complex karyotypes and clonal evolution was associated with progressive form of disease (P 0,000003, resp. P 0,0002 and P 0,05/P 0,04). In cases of the recurrent deletions the detailed analysis of metaphase...
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Genomic abberations in brain glioma cells
Šediváková, Kristýna ; Zemanová, Zuzana (advisor) ; Březinová, Jana (referee)
Brain gliomas represent a heterogeneous group of tumors of various histological subtypes which differ according to their response to treatment and prognosis. Tumors created from astrocytes and oligodendrocytes occur most often. During brain tumor onset and progression, the genomic aberrations in brain glioma cells play an important role. Diagnostic detection of diffuse glioma tumors based on cell morphology is subjective. Due to their locations and diffuse character, glioma treatment is still a problematical issue. Therefore, new diagnostic and prognostic techniques must be developed which would make a more effective treatment possible, resulting thus in lower morbidity and mortality rates. An option is to sub-classify patients into diagnostic groups based on detection of specific chromosome aberrations detected by combination of I-FISH and microarray techniques. Use of molecular cytogenetic methods not only contributes to more precise diagnosis and prognosis for patients with diffuse glioms, but also to better understanding of the pathogenesis of brain tumors. Keywords: Brain glioma, genomic aberrations, astrocytic tumors, oligodendroglial tumors, molecular cytogenetic methods
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