Deletion 20q is a recurrent abnormality in myeloid malignancies. In our previous study, we identified fusion of the additional sex combs-like 1 (ASXL1) and teashirt zinc finger homeobox 2 genes in a patient with myelodysplastic syndrome. The objective of this study was to determine the frequency of ASXL1 breakpoints in a cohort of 36 patients with deletion 20q as the sole cytogenetic aberration. A combination of molecular cytogenetic methods was used to confirm ASXL1 gene alterations in 19 of the 36 patients, and the determination of ASXL1 gene changes in patients with deletion 20q revealed clinical and prognostic impacts.

• MeSH
• Chromosome Deletion * MeSH
• Cytogenetic Analysis MeSH
• Humans MeSH
• Chromosomes, Human, Pair 20 genetics   MeSH
• Myelodysplastic Syndromes genetics   MeSH
• Repressor Proteins genetics   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

• Publication type
• Meeting Abstract MeSH

• Publication type
• Meeting Abstract MeSH

Complex karyotypes are seen in approximately 20% of patients with myelodysplastic syndromes (MDS) and are associated with a high risk of transformation to acute myeloid leukemia and poor outcomes in patients. Copy number neutral loss of heterozygosity (CN-LOH, i.e., both copies of a chromosomal pair or their parts originate from one parent) might contribute to increased genomic instability in the bone-marrow cells of patients with MDS. The pathological potential of CN-LOH, which arises as a clonal aberration in a proportion of somatic cells, consists of tumor suppressor gene and oncogene homozygous mutations. The aim of our study was to evaluate the frequency of CN-LOH at 17p in bone-marrow cells of newly diagnosed MDS patients with complex chromosomal aberrations and to assess its correlation with mutations in the TP53 gene (17p13.1). CN-LOH was detected in 40 chromosomal regions in 21 (29%) of 72 patients analyzed. The changes in 27 of the 40 regions identified were sporadic. The most common finding was CN-LOH of the short arm of chromosome 17, which was detected in 13 (18%) of 72 patients. A mutational analysis confirmed the homozygous mutation of TP53 in all CN-LOH 17p patients, among which two frameshift mutations are not registered in the International Agency for Research on Cancer TP53 Database. CN-LOH 17p correlated with aggressive disease (median overall survival 4 months) and was strongly associated with a complex karyotype in the cohort studied, which might cause rapid disease progression in high-risk MDS. No other CN-LOH region previously recorded in MDS or AML patients (1p, 4q, 7q, 11q, 13q, 19q, 21q) was detected in our cohort of patients with complex karyotype examined at the diagnosis of MDS. The LOH region appeared to be balanced (i.e., with no DNA copy number change) when examined with conventional and molecular cytogenetic methods. Therefore, a microarray that detects single-nucleotide polymorphisms is an ideal method with which to identify and further characterize CN-LOH. Our data should specify the prognosis and should lead to the identification of potential targets for therapeutic interventions.

• MeSH
• Chromosome Aberrations * MeSH
• Adult MeSH
• Gene Dosage * MeSH
• In Situ Hybridization, Fluorescence MeSH
• Polymorphism, Single Nucleotide MeSH
• Middle Aged MeSH
• Humans MeSH
• Chromosomes, Human, Pair 17 genetics   MeSH
• Mutation MeSH
• DNA Mutational Analysis MeSH
• Myelodysplastic Syndromes genetics   MeSH
• Tumor Suppressor Protein p53 genetics   MeSH
• Retrospective Studies MeSH
• Oligonucleotide Array Sequence Analysis MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• DNA Copy Number Variations MeSH
• High-Throughput Nucleotide Sequencing MeSH
• Loss of Heterozygosity genetics   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

U 10–20 % nemocných s myelodysplastickými syndromy (MDS) je nalézán komplexní karyotyp, který je spojen s vysokým rizikem transformace do akutní myeloidní leukemie (AML) a špatnou prognózou. Jedním z jevů, které se mohou podílet na zvýšené genomové nestabilitě buněk kostní dřeně u nemocných s MDS, je získaná uniparentální disomie (aUPD), tj. stav, kdy obě kopie určitého chromozomu nebo jeho části pochází od jednoho rodiče. Patologický potenciál této změny, která vzniká jako klonální aberace v některých somatických buňkách, spočívá v přítomnosti homozygotních mutací tumor supresorových genů a onkogenů. Cílem studie bylo zjistit frekvenci a význam uniparentální disomie (UPD) v souboru 57 nemocných s MDS a komplexním karyotypem za použití array komparativní genomové hybridizace kombinované s detekcí jednonukleotidových polymorfismů (aCGH/SNP). V souboru 57 nemocných bylo nalezeno celkem 40 oblastí UPD u 21 pacientů (36,8 %). U zhruba poloviny nálezů šlo o sporadický výskyt (19/40). U šesti pacientů byly detekovány UPD na chromozomu X lokalizované v oblastech Xp22.11–Xp22.2 (4/6) a Xq13.3–Xq21.1 (2/6) a u dvou pacientů byla pozorována UPD 17q s proměnlivým rozsahem v pruzích 17q22 až 17q24.2. Nejčastějším nálezem byla aUPD krátkých ramen chromozomu 17, která byla detekována celkem u 13/57 pacientů (22,8 %). U všech 13 pacientů mutační analýza potvrdila homozygotní mutaci genu TP53, z toho dvě nalezené posunové (frameshift) mutace nebyly dosud popsány v databázi IARC (International Agency for Research on Cancer TP53 database). Nález byl spojen s velmi špatnou prognózou (medián přežití 4 měsíce). Vzhledem k četnosti výskytu ve studovaném souboru byla aUPD 17p silně asociována s komplexním karyotypem na rozdíl od jiných v literatuře dosud popsaných oblastí aUPD (1p, 4q, 7q, 11q, 13q, 21q), které nebyly v souboru detekovány vůbec. Oblasti UPD se jeví při analýzách metodami klasické a molekulární cytogenetiky jako balancované, tedy bez změny počtu kopií DNA. Čipové technologie s detekcí jednonukleotidových polymorfismů jsou ideální metodou pro identifikaci a bližší charakterizaci oblastí UPD a s nimi souvisejících genů významných pro vznik a progresi onemocnění.

Complex karyotypes are seen in approximately 20% of patients with myelodysplastic syndromes (MDS) and are associated with a high risk of transformation into acute myeloid leukaemia (AML) and poor prognosis. Acquired uniparental disomy (aUPD, i.e. both copies of a chromosome pair or its part originate from one parent) may contribute to increased genomic instability in bone-marrow cells of patients with MDS. The pathological potential of aUPD, which arises as a clonal aberration in a proportion of somatic cells, involves tumour suppressor gene and oncogene homozygous mutations. The aim of this study was to evaluate the frequency and implications of uniparental disomy (UPD) in a cohort of 57 patients with MDS and complex karyotype using array comparative genomic hybridization with detection of single nucleotide polymorphisms (aCGH/SNP). UPD was found to be present in 40 regions in 21 of 57 patients (36.8%). Almost half of these involved non-recurrent changes (19/40). Chromosome X UPD was detected in six patients (Xp22.11–Xp22.2 in four and Xq13.3–Xq21.1 in two, respectively). UPD of 17q with a variable extent from 17q22 to 17q24.2 was observed in two patients. The most common finding was aUPD of the short arm of chromosome 17, which was detected in 13 of 57 patients (22.8%). Mutational analysis confirmed a homozygous mutation of the TP53 gene in all samples with this finding, including two frameshift mutations that are not registered in the IARC (International Agency for Research on Cancer TP53) database. This finding correlated with very poor prognosis (median OS 4 months). aUPD 17p was strongly associated with complex karyotype in the studied cohort. However, other previously published aUPDs in MDS (1p, 4q, 7q, 11q, 13q, 21q) were not found in our study. UPD regions appear to be balanced (i.e. without change of DNA copies) by conventional and molecular cytogenetic methods. Therefore, aCGH/SNP represents an ideal method for the identification and further characterization of UPDs and affected genes significant for disease development and progression.

• Keywords
• komplexní karyotyp, refrakterní cytopenie s multilineární dysplazií,
• MeSH
• Leukemia, Myeloid, Acute genetics   MeSH
• Survival Analysis MeSH
• Chromosome Deletion MeSH
• Adult MeSH
• Genes, p53 * genetics   MeSH
• Homozygote MeSH
• Polymorphism, Single Nucleotide MeSH
• Karyotype MeSH
• Middle Aged MeSH
• Humans MeSH
• Chromosomes, Human, Pair 17 genetics   MeSH
• Mutation MeSH
• DNA Mutational Analysis MeSH
• Myelodysplastic Syndromes * genetics   MeSH
• Anemia, Refractory, with Excess of Blasts genetics   MeSH
• Retrospective Studies MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Comparative Genomic Hybridization statistics & numerical data   MeSH
• Uniparental Disomy * genetics   MeSH
• Bone Marrow Examination MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Research Support, Non-U.S. Gov't MeSH

• Publication type
• Meeting Abstract MeSH

• Publication type
• Meeting Abstract MeSH

Gene amplification is a frequent genetic abnormality in solid tumors, and many oncogenes are activated in this way. In acute myeloid leukemia (AML), a frequent target of gene amplification is chromosome 11, particularly chromosome region 11q23, including the MLL (myeloid/lymphoid leukemia) gene. However, the number of other amplicons from the long arm of chromosome 11 has also been described. Duplication/amplification of chromosome 11 was found by cytogenetic methods in 10 of 119 newly diagnosed patients with AML. The amplification was presented as: amplification including only the 5' segment of the MLL gene (1 patient), trisomy 11 (3 patients), partial trisomy 11q (2 patients), isochromosome 11q (1 patient), and multiple amplification of specific regions (3 patients). In two cases, amplification involved parts of not only long arm but also of short arm of the chromosome 11: 11p15 and 11p11.1 to 11p13.

• MeSH
• Leukemia, Myeloid, Acute diagnosis   genetics   MeSH
• Gene Amplification MeSH
• Adult MeSH
• Gene Duplication MeSH
• In Situ Hybridization, Fluorescence MeSH
• Karyotyping MeSH
• Middle Aged MeSH
• Humans MeSH
• Chromosomes, Human, Pair 11 genetics   MeSH
• Prognosis MeSH
• Aged MeSH
• Trisomy MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Telomere length was evaluated by terminal repeat fragment method in 66 previously untreated patients with B-chronic lymphocytic leukemia (B-CLL) to ascertain whether telomere shortening was associated with genomic aberrations, immunoglobulin variable heavy chain (IgVH) mutational status, CD38 and ZAP-70 expression, and telomerase activity. Chromosomal aberrations were present in peripheral blood cells of 73% patients (48/66), no difference in telomere length between patients with good and intermediate prognosis according to cytogenetics was found. Association between telomere length and IgVH mutational status, ZAP-70 and CD38 expression was proved as significantly shorter telomeres in patients with unmutated IgVH status (p=0.01) and ZAP-70 positivity (p=0.01) and CD38 positivity (p=0.05) were detected. Telomerase activity was positive in 11 patients out of 21 examined, correlation between telomere length and telomerase activity was found (p=0.05). Telomere length and telomerase activity in combination with other prognostic parameters complete the risk profile of B-CLL patients and might serve for an easy decision on optimal treatment strategy. Keywords: B-chronic lymphocytic leukemia, telomere length, telomerase activity, chromosomal aberrations, prognosis.

• MeSH
• ADP-ribosyl Cyclase 1 analysis   MeSH
• Chromosome Aberrations MeSH
• Leukemia, Lymphocytic, Chronic, B-Cell genetics   immunology   metabolism   MeSH
• Adult MeSH
• Immunophenotyping MeSH
• Middle Aged MeSH
• Humans MeSH
• Mutation MeSH
• ZAP-70 Protein-Tyrosine Kinase analysis   MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Telomere MeSH
• Immunoglobulin Heavy Chains genetics   MeSH
• Immunoglobulin Variable Region genetics   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH