RESUMO
We assessed the prognostic impact of TET2 mutations and mRNA expression in a prospective cohort of 357 adult AML patients < 60 years of age enrolled in the European Organization For Research and Treatment of Cancer (EORTC)/Gruppo Italiano Malattie Ematologiche dell' Adulto (GIMEMA) AML-12 06991 clinical trial. In addition the co-occurrence with other genetic defects and the functional consequences of TET2 mutations were investigated. TET2 mutations occurred in 7.6 % of the patients and were an independent marker of poor prognosis (p = 0.024). TET2 and IDH1/2 mutations strongly associated with aberrations in the DNA methyltransferase DNMT3A. Functional studies confirmed previous work that neither nonsense truncations, nor missense TET2 mutations, induced 5-hydroxymethylcytosine formation. In addition, we now show that mutant TET2 forms did not act in a dominant negative manner when co-expressed with the wild-type protein. Finally, as loss-of-function TET2 mutations predicted poor outcome, we questioned whether low TET2 mRNA expression in cases of AML without TET2 mutations would affect overall survival. Notably, also AML patients with low TET2 mRNA expression levels showed inferior overall survival.
Assuntos
Proteínas de Ligação a DNA/genética , Regulação Leucêmica da Expressão Gênica , Leucemia Mieloide Aguda/genética , Mutação , Proteínas de Neoplasias/genética , Proteínas Proto-Oncogênicas/genética , 5-Metilcitosina/análogos & derivados , Adolescente , Adulto , Animais , Células COS , Chlorocebus aethiops , Ensaios Clínicos como Assunto , Citosina/análogos & derivados , Citosina/análise , DNA (Citosina-5-)-Metiltransferases/genética , DNA Metiltransferase 3A , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/fisiologia , Dioxigenases , Feminino , Humanos , Isocitrato Desidrogenase/genética , Estimativa de Kaplan-Meier , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/mortalidade , Masculino , Estudos Multicêntricos como Assunto , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/fisiologia , Prognóstico , Estudos Prospectivos , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas/fisiologia , RNA Mensageiro/biossíntese , RNA Neoplásico/biossíntese , Proteínas Recombinantes de Fusão/metabolismo , Transfecção , Adulto JovemRESUMO
Cancer development is a dynamic process during which the successive accumulation of mutations results in cells with increasingly malignant characteristics. Here, we show the clonal evolution pattern in myelodysplastic syndrome (MDS) patients receiving supportive care, with or without lenalidomide (follow-up 2.5-11 years). Whole-exome and targeted deep sequencing at multiple time points during the disease course reveals that both linear and branched evolutionary patterns occur with and without disease-modifying treatment. The application of disease-modifying therapy may create an evolutionary bottleneck after which more complex MDS, but also unrelated clones of haematopoietic cells, may emerge. In addition, subclones that acquired an additional mutation associated with treatment resistance (TP53) or disease progression (NRAS, KRAS) may be detected months before clinical changes become apparent. Monitoring the genetic landscape during the disease may help to guide treatment decisions.
Assuntos
Inibidores da Angiogênese/uso terapêutico , Biomarcadores Tumorais/genética , Células da Medula Óssea/efeitos dos fármacos , Evolução Clonal/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , Talidomida/análogos & derivados , Idoso , Biomarcadores Tumorais/metabolismo , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Gerenciamento Clínico , Progressão da Doença , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Seguimentos , GTP Fosfo-Hidrolases/genética , GTP Fosfo-Hidrolases/metabolismo , Humanos , Lenalidomida , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Pessoa de Meia-Idade , Monitorização Fisiológica , Mutação , Síndromes Mielodisplásicas/tratamento farmacológico , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/metabolismo , Síndromes Mielodisplásicas/patologia , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Talidomida/uso terapêutico , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Sequenciamento do ExomaRESUMO
In normal bone marrow, WT1 expression is restricted to CD34+ cells. We assessed WT1 mRNA expression levels with quantitative, real-time reverse transcription polymerase chain reaction in normal, myelodysplastic (MDS) and secondary acute myeloid leukaemia (sAML) bone marrow subfractions, based on differentiation status. The highest WT1 expression was observed in the primitive CD34+ rhodamine-123 (rho) dull cells, both in healthy donors and MDS or sAML patients. In contrast to normal CD34-negative bone marrow cells, WT1 was present in CD34-negative bone marrow cells in 12 out of 13 MDS patients and two sAML samples. Further analysis of this aberrant WT1 expression was performed in the CD34-negative subfractions of three MDS patients. In one of these, WT1 expression was found exclusively in the erythroid cells. This patient was completely transfusion dependent and showed morphological dyserythropoiesis. In another MDS patient, WT1 expression was found in a non-erythroid compartment. We conclude that abnormal WT1 expression may contribute to the disturbed differentiation of haematopoietic cells in MDS patients.