RESUMO
Constitutively activated FLT3 signaling is common in acute myeloid leukemia, and is currently under evaluation for targeted therapy, whereas little data is available in T-cell acute lymphoblastic leukemia (T-ALL). We analyzed 357 T-ALL cases for FLT3 mutations and transcript expression. FLT3 mutations (3% overall) and overexpression (FLT3 high expresser (FLT3(High))) were restricted to immature/TCRγδ T-ALLs. In vitro FLT3 inhibition induced apoptosis in only 30% of FLT3(High) T-ALLs and did not correlate with mutational status. In order to investigate the mechanisms of primary resistance to FLT3 inhibition, a broad quantitative screen for receptor kinome transcript deregulation was performed by Taqman Low Density Array. FLT3 deregulation was associated with overexpression of a network of receptor kinases (RKs), potentially responsible for redundancies and sporadic response to specific FLT3 inhibition. In keeping with this resistance to FLT3 inhibition could be reversed by dual inhibition of FLT3 and KIT with a synergistic effect. We conclude that immature T-ALL may benefit from multitargeted RK inhibition and that exploration of the receptor kinome defines a rational strategy for testing multitarget kinase inhibition in malignant diseases.
Assuntos
Apoptose/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Mutação/genética , Leucemia-Linfoma Linfoblástico de Células T Precursoras/enzimologia , Inibidores de Proteínas Quinases/farmacologia , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , DNA de Neoplasias/genética , Sinergismo Farmacológico , Feminino , Citometria de Fluxo , Seguimentos , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Leucemia-Linfoma Linfoblástico de Células T Precursoras/genética , Prognóstico , Receptores Proteína Tirosina Quinases/genética , Receptores Proteína Tirosina Quinases/metabolismo , Transdução de Sinais , Taxa de Sobrevida , Células Tumorais Cultivadas , Adulto Jovem , Tirosina Quinase 3 Semelhante a fms/genética , Tirosina Quinase 3 Semelhante a fms/metabolismoRESUMO
Chromosomal rearrangements of the human MLL gene are associated with high-risk pediatric, adult and therapy-associated acute leukemias. These patients need to be identified, treated appropriately and minimal residual disease was monitored by quantitative PCR techniques. Genomic DNA was isolated from individual acute leukemia patients to identify and characterize chromosomal rearrangements involving the human MLL gene. A total of 760 MLL-rearranged biopsy samples obtained from 384 pediatric and 376 adult leukemia patients were characterized at the molecular level. The distribution of MLL breakpoints for clinical subtypes (acute lymphoblastic leukemia, acute myeloid leukemia, pediatric and adult) and fused translocation partner genes (TPGs) will be presented, including novel MLL fusion genes. Combined data of our study and recently published data revealed 104 different MLL rearrangements of which 64 TPGs are now characterized on the molecular level. Nine TPGs seem to be predominantly involved in genetic recombinations of MLL: AFF1/AF4, MLLT3/AF9, MLLT1/ENL, MLLT10/AF10, MLLT4/AF6, ELL, EPS15/AF1P, MLLT6/AF17 and SEPT6, respectively. Moreover, we describe for the first time the genetic network of reciprocal MLL gene fusions deriving from complex rearrangements.
Assuntos
Leucemia/genética , Proteína de Leucina Linfoide-Mieloide/genética , Proteínas de Neoplasias/genética , Proteínas de Fusão Oncogênica/genética , Recombinação Genética , Translocação Genética , Doença Aguda , Adulto , Biópsia , Medula Óssea/química , Medula Óssea/patologia , Criança , Quebra Cromossômica , Cromossomos Humanos Par 11/genética , Cromossomos Humanos Par 11/ultraestrutura , Biologia Computacional , DNA de Neoplasias/sangue , DNA de Neoplasias/genética , Duplicação Gênica , Histona-Lisina N-Metiltransferase , Humanos , Reação em Cadeia da PolimeraseAssuntos
Linfoma de Burkitt/genética , Cromossomos Humanos Par 10/genética , Cromossomos Humanos Par 9/genética , Proteínas de Fusão Oncogênica/genética , Proteínas Proto-Oncogênicas c-abl/genética , Fatores de Transcrição/genética , Translocação Genética/genética , Sequência de Aminoácidos , Sequência de Bases , Linfoma de Burkitt/patologia , Feminino , Humanos , Hibridização in Situ Fluorescente , Lactente , Dados de Sequência MolecularRESUMO
A complete blood analysis with a careful morphologic examination of peripheral blood and bone morrow smears completed by cytochemical reaction will help to classify the most acute myeloid leukaemia (AML). Actually, the study of other cytogenetis and immunophenotypic markers are now necessary to confirm diagnosis. The World Health Organisation WHO classification (2001) incorporates theses approaches. The purpose of this study is a bio-clinical review according to the WHO recommendations in 153 cases of LAM diagnosed between January 1998 and December 2003. The patients were aged 2 months to 90 years with sex ratio (M/F) of 1,22. The morphologic conclusion was difficult in 12% cases. Presence of dysplasia is noted in 50% of cases with multilineage dysplasia in 42% of cases. Our results showed cloned chromosomal abnormalities in 57% of cases (t(8;21): 12%, t(15;17) : 10%, Inv16: 1,3%, 11q23: 2,6% et complex karyotype: 14,3%). In 69% of cases with multilineage dysplasia, the karyotype was normal. 3 cases of LAM were noted at patients treated for breast cancer with chirurgic chemotherapy and radiotherapy 3, 4 et 5 years after treatment (LAM3 with t(15;17), LAM4 with genetic abnormalities of chromosomes 3, 5, 7, 8, 9, 14 et 16 et LAM 6 with genetic abnormalities of chromosomes 4, 7, 12, 14, 19 et 21). In WHO classification, cytology is essential in diagnosis of LAM even if the karytype have an important prognostic value. Research of signs of dysplasia lineage after lineage constitutes an important microscopic work and it is difficult to quantify dysplasia when the lineage is poor.
Assuntos
Leucemia Mieloide/classificação , Doença Aguda , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Aberrações Cromossômicas , Diagnóstico Diferencial , Feminino , Humanos , Lactente , Cariotipagem , Leucemia Eritroblástica Aguda/sangue , Leucemia Eritroblástica Aguda/diagnóstico , Leucemia Eritroblástica Aguda/genética , Leucemia Mieloide/sangue , Leucemia Mieloide/diagnóstico , Leucemia Mieloide/genética , Leucemia Mielomonocítica Aguda/sangue , Leucemia Mielomonocítica Aguda/diagnóstico , Leucemia Mielomonocítica Aguda/genética , Leucemia Promielocítica Aguda/sangue , Leucemia Promielocítica Aguda/diagnóstico , Leucemia Promielocítica Aguda/genética , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Tunísia , Organização Mundial da SaúdeRESUMO
The NUP98 gene is fused with 19 different partner genes in various human hematopoietic malignancies. In order to gain additional clinico-hematological data and to identify new partners of NUP98, the Groupe Francophone de Cytogénétique Hématologique (GFCH) collected cases of hematological malignancies where a 11p15 rearrangement was detected. Fluorescence in situ hybridization (FISH) analysis showed that 35% of these patients (23/66) carried a rearrangement of the NUP98 locus. Genes of the HOXA cluster and the nuclear-receptor set domain (NSD) genes were frequently fused to NUP98, mainly in de novo myeloid malignancies whereas the DDX10 and TOP1 genes were equally rearranged in de novo and in therapy-related myeloid proliferations. Involvement of ADD3 and C6ORF80 genes were detected, respectively, in myeloid disorders and in T-cell acute lymphoblastic leukemia (T-ALL), whereas the RAP1GDS1 gene was fused to NUP98 in T-ALL. Three new chromosomal breakpoints: 3q22.1, 7p15 (in a localization distinct from the HOXA locus) and Xq28 were detected in rearrangements with the NUP98 gene locus. The present study as well as a review of the 73 cases previously reported in the literature allowed us to delineate some chromosomal, clinical and molecular features of patients carrying a NUP98 gene rearrangements.