RESUMO
Two different systems exist for subclassification of acute myeloid leukemia (AML); the World Health Organization (WHO) Classification and the International Consensus Classification (ICC) of myeloid malignancies. The two systems differ in their classification of AML defined by recurrent chromosomal abnormalities. One difference is that the ICC classification defines an AML subset that includes 12 different genetic abnormalities that occur in less than 4% of AML patients. These subtypes exhibit distinct clinical traits and are associated with treatment outcomes, but detailed description of these entities is not easily available and is not described in detail even in the ICC. We searched in the PubMed database to identify scientific publications describing AML patients with the recurrent chromosomal abnormalities/translocations included in this ICC defined patient subset. This patient subset includes AML with t(1;3)(p36.3;q21.3), t(3;5)(q25.3;q35.1), t(8;16)(p11.2;p13.3), t(1;22)(p13.3;q13.1), t(5;11)(q35.2;p15.4), t(11;12)(p15.4;p13.3) (involving NUP98), translocation involving NUP98 and other partner, t(7;12)(q36.3;p13.2), t(10;11)(p12.3;q14.2), t(16;21)(p11.2;q22.2), inv(16)(p13.3q24.3) and t(16;21)(q24.3;q22.1). In this updated review we describe the available information with regard to frequency, biological functions of the involved genes and the fusion proteins, morphology/immunophenotype, required diagnostic procedures, clinical characteristics (including age distribution) and prognostic impact for each of these 12 genetic abnormalities.
Assuntos
Leucemia Mieloide Aguda , Translocação Genética , Humanos , Consenso , Leucemia Mieloide Aguda/diagnóstico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Aberrações Cromossômicas , Prognóstico , RecidivaRESUMO
BACKGROUND/AIM: Constitutional chromosomal aberrations are rare in hematologic malignancies and their pathogenetic role is mostly poorly understood. We present a comprehensive molecular characterization of a novel constitutional chromosomal translocation found in two siblings - sisters - diagnosed with myelodysplastic syndrome (MDS). MATERIALS AND METHODS: Bone marrow and blood cells from the two patients were examined using G-banding, RNA sequencing, PCR, and Sanger sequencing. RESULTS: We identified a balanced t(17;19)(q21;p13) translocation in both siblings' bone marrow, blood cells, and phytohemagglutinin-stimulated lymphocytes. The translocation generated a MYO1F::WNK4 chimera on the der(19)t(17;19), encoding a chimeric serine/threonine kinase, and a VPS25::MYO1F on the der(17), potentially resulting in an aberrant VPS25 protein. CONCLUSION: The t(17;19)(q21;p13) translocation found in the two sisters probably predisposed them to myelodysplasia. How the MYO1F::WNK4 and/or VPS25::MYO1F chimeras, perhaps especially MYO1F::WNK4 that encodes a chimeric serine/threonine kinase, played a role in MDS pathogenesis, remains incompletely understood.
Assuntos
Síndromes Mielodisplásicas , Irmãos , Translocação Genética , Humanos , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/patologia , Feminino , Cromossomos Humanos Par 17/genética , Cromossomos Humanos Par 19/genética , Proteínas Serina-Treonina Quinases/genética , Proteínas de Transporte Vesicular/genética , Proteínas de Fusão Oncogênica/genética , Pessoa de Meia-IdadeRESUMO
BACKGROUND/AIM: The aim of the study was to determine the genetic and molecular consequences of trisomy 4, a recurrent but rare chromosomal abnormality in acute myeloid leukemia (AML). MATERIALS AND METHODS: Interphase fluorescence in situ hybridization, reverse transcriptase-quantitative polymerase chain reaction for 28 chromosomal gene translocations/fusion genes, and targeted sequencing analyses were performed on five AMLs with trisomy 4 as the sole chromosomal anomaly. RESULTS: An NPM1 frameshift mutation was found in all leukemic bone marrows, DNMT3A, FLT3, and IDH1 mutations were found in three, KIT and NRAS mutations in two, whereas IDH2 (R140Q), RUNX1, and WT1 mutations were found in only one patient each. The three patients with a DNMT3A (R882H) mutation have died. In contrast, the two patients whose leukemic cells were without this mutation, are alive 55 and 31 months after diagnosis, respectively. CONCLUSION: The results suggest a possible association between trisomy 4 and additional mutations that may influence prognosis.
Assuntos
Aberrações Cromossômicas , Cromossomos Humanos Par 4/genética , Leucemia Mieloide Aguda/genética , Trissomia , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Feminino , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/patologia , Masculino , Pessoa de Meia-Idade , Nucleofosmina , PrognósticoRESUMO
RNA-sequencing of the patient's bone marrow detected fusion transcripts in which the coding sequence of the FAM53B gene (from 10q26) was fused to a genomic sequence (from 19q13) that mapped upstream of the SLC7A10 locus. Reverse transcription-polymerase chain reaction together with Sanger sequencing verified the presence of this fusion transcript. The FAM53B fusion transcript is not expected to produce any chimeric protein. However, it may code for a truncated FAM53B protein consisting of the first 302 amino acids of FAM53B together with amino acids from the 19q13 sequence. Functionally, the truncated FAM53B would be similar to the protein encoded by the FAM53B sequence with accession no. BC031654.1 (FAM53B protein accession no. AAH31654.1). Furthermore, the truncated protein contains the entire conserved domain of the FAM53 protein family. The chromosome aberration t(10;19)(q26;q13) detected in this study was previously reported in a single case of ALL, in which it was also the sole karyotypic change. Both patients entered complete hematological and cytogenetic remission following treatment.
RESUMO
BACKGROUND/AIM: Given the diagnostic, prognostic, biologic, and even therapeutic impact of leukemia-associated translocations and fusion genes, it is important to detect cryptic genomic rearrangements that may exist in hematological malignancies. CASE REPORT: RNA-sequencing was performed on an acute myeloid leukemia case with the bone marrow karyotype 45,X,-Y,t(9;12) (q34;q15)[16]. RESULTS: The DEK-NUP214 and PRRC2B-DEK fusion genes were found. Reverse transcriptase polymerase chain reaction together with direct sequencing verified the presence of both. Fluorescence in situ hybridization showed that the DEK-NUP214 fusion gene was located on the 6p22 band of a seemingly normal chromosome 6. CONCLUSION: RNA-sequencing proved to be a valuable tool for the detection of a fusion of genes DEK and NUP214 in a leukemia that showed cryptic cytogenetic rearrangement of chromosome band 9q34.
Assuntos
Proteínas Cromossômicas não Histona/genética , Leucemia Mieloide Aguda/genética , Complexo de Proteínas Formadoras de Poros Nucleares/genética , Proteínas de Fusão Oncogênica/genética , Proteínas Oncogênicas/genética , Proteínas de Ligação a Poli-ADP-Ribose/genética , Análise de Sequência de RNA/métodos , Fatores de Transcrição/genética , Adulto , Proteínas Cromossômicas não Histona/metabolismo , Humanos , Leucemia Mieloide Aguda/patologia , Masculino , Complexo de Proteínas Formadoras de Poros Nucleares/metabolismo , Proteínas Oncogênicas/metabolismo , Proteínas de Ligação a Poli-ADP-Ribose/metabolismo , Adulto JovemRESUMO
BACKGROUND/AIM: New chromosomal aberrations continue to be reported in acute myeloid leukemias (AML). The addition of more cases with the same genetic characteristics would establish an acquired aberration as a recurrent change, help determine its prognostic significance, and can provide insight into the mechanisms of leukemogenesis in patients with these rare abnormalities. CASE REPORT: RNA-sequencing was performed on a patient with AML with the bone marrow karyotype 46,XY,t(3;5)(p24;q14)[5]/46,XY[10]. The translocation resulted in fusion of the SATB homeobox 1 gene (SATB1) (3p24) with an expression sequence tag with accession number BG503445 (5q14). The SATB1-BG503445 transcript may code for a SATB1 protein that would lack the C-terminal DNA-binding homeodomain. CONCLUSION: The present study is the first to demonstrate rearrangement and disruption of SATB1 in AML. Rearrangements of chromosome band 3p24 were reported in 24 additional AMLs but not in known leukemia-specific chromosomal abnormalities. Further studies are needed to determine whether SATB1-BG503445 or other aberrations of SATB1 are recurrent in AML.
Assuntos
Cromossomos Humanos Par 3/genética , Cromossomos Humanos Par 5/genética , Rearranjo Gênico , Leucemia Mieloide/genética , Proteínas de Ligação à Região de Interação com a Matriz/genética , Translocação Genética , Doença Aguda , Idoso , Bandeamento Cromossômico , Humanos , Hibridização in Situ Fluorescente , Cariotipagem , Leucemia Mieloide/diagnóstico , Masculino , Proteínas de Fusão Oncogênica/genéticaRESUMO
Fluorescence in situ hybridization examination of a pediatric AML patient whose bone marrow cells carried trisomy 4 and FLT3-ITD mutation, demonstrated that part of the RUNX1 probe had unexpectedly moved to chromosome band 6q25 indicating a cryptic t(6;21)(q25;q22) translocation. RNA sequencing showed fusion of exon 7 of RUNX1 with an intergenic sequence of 6q25 close to the MIR1202 locus, something that was verified by RT-PCR together with Sanger sequencing. The RUNX1 fusion transcript encodes a truncated protein containing the Runt homology domain responsible for both heterodimerization with CBFB and DNA binding, but lacking the proline-, serine-, and threonine-rich (PST) region which is the transcription activation domain at the C terminal end. Which genetic event (+4, FLT3-ITD, t(6;21)-RUNX1 truncation or other, undetected acquired changes) was more pathogenetically important in the present case of AML, remains unknown. The case illustrates that submicroscopic chromosomal rearrangements may accompany visible numerical changes and perhaps should be actively looked for whenever a single trisomy is found. An active search for them may provide both pathogenetic and prognostic novel information.
Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/genética , Leucemia Mieloide Aguda/genética , Proteínas de Fusão Oncogênica/genética , Translocação Genética/genética , Criança , Cromossomos Humanos Par 21/genética , Cromossomos Humanos Par 6/genética , Feminino , Humanos , Hibridização in Situ Fluorescente , Leucemia Mieloide Aguda/patologia , Análise de Sequência de RNARESUMO
RNA-sequencing of a case of acute myeloid leukemia with the bone marrow karyotype 46,XY,t(2;14)(q22;q32)[5]/47,XY,idem,+?4,del(6)(q13q21)[cp6]/46,XY[4] showed that the t(2;14) generated a ZEB2-BCL11B chimera in which exon 2 of ZEB2 (nucleotide 595 in the sequence with accession number NM_014795.3) was fused to exon 2 of BCL11B (nucleotide 554 in the sequence with accession number NM_022898.2). RT-PCR together with Sanger sequencing verified the presence of the above-mentioned fusion transcript. All functional domains of BCL11B are retained in the chimeric protein. Abnormal expression of BCL11B coding regions subjected to control by the ZEB2 promoter seems to be the leukemogenic mechanism behind the translocation.
Assuntos
Cromossomos Humanos Par 14/genética , Cromossomos Humanos Par 2/genética , Leucemia Mieloide Aguda/genética , Proteínas Mutantes Quiméricas/genética , Proteínas de Fusão Oncogênica/genética , Análise de Sequência de RNA , Translocação Genética , Adulto , Sequência de Bases , Aberrações Cromossômicas , Bandeamento Cromossômico , Evolução Fatal , Humanos , Masculino , Dados de Sequência Molecular , Reação em Cadeia da Polimerase em Tempo Real , Reprodutibilidade dos TestesRESUMO
An acute myeloid leukemia was suspected of having a t(8;16)(p11;p13) resulting in a KAT6A-CREBBP fusion because the bone marrow was packed with monoblasts showing marked erythrophagocytosis. The diagnostic karyotype was 46,XY,add(1)(p13),t(8;21)(p11;q22),der(16)t(1;16)(p13;p13)[9]/46,XY[1]; thus, no direct confirmation of the suspicion could be given although both 8p11 and 16p13 seemed to be rearranged. The leukemic cells were examined in two ways to find out whether a cryptic KAT6A-CREBBP was present. The first was the "conventional" approach: G-banding was followed by fluorescence in situ hybridization (FISH) and reverse transcription PCR (RT-PCR). The second was RNA-Seq followed by data analysis using FusionMap and FusionFinder programs with special emphasis on candidates located in the 1p13, 8p11, 16p13, and 21q22 breakpoints. FISH analysis indicated the presence of a KAT6A/CREBBP chimera. RT-PCR followed by Sanger sequencing of the amplified product showed that a chimeric KAT6A-CREBBP transcript was present in the patients bone marrow. Surprisingly, however, KATA6A-CREBBP was not among the 874 and 35 fusion transcripts identified by the FusionMap and FusionFinder programs, respectively, although 11 sequences of the raw RNA-sequencing data were KATA6A-CREBBP fragments. This illustrates that although many fusion transcripts can be found by RNA-Seq combined with FusionMap and FusionFinder, the pathogenetically essential fusion is not always picked up by the bioinformatic algorithms behind these programs. The present study not only illustrates potential pitfalls of current data analysis programs of whole transcriptome sequences which make them less useful as stand-alone techniques, but also that leukemia diagnosis still relies on integration of clinical, hematologic, and genetic disease features of which the former two by no means have become superfluous.