RESUMO
Severe congenital neutropenia (CN) is a preleukemic bone marrow failure syndrome with a 20% risk of evolving into leukemia or myelodysplastic syndrome (MDS). Patterns of acquisition of leukemia-associated mutations were investigated using next-generation deep-sequencing in 31 CN patients who developed leukemia or MDS. Twenty (64.5%) of the 31 patients had mutations in RUNX1. A majority of patients with RUNX1 mutations (80.5%) also had acquired CSF3R mutations. In contrast to their high frequency in CN patients who developed leukemia or MDS, RUNX1 mutations were found in only 9 of 307 (2.9%) patients with de novo pediatric acute myeloid leukemia. A sequential analysis at stages prior to overt leukemia revealed RUNX1 mutations to be late events in leukemic transformation. Single-cell analyses in 2 patients showed that RUNX1 and CSF3R mutations were present in the same malignant clone. Functional studies demonstrated elevated granulocyte colony-stimulating factor (G-CSF)-induced proliferation with diminished myeloid differentiation of hematopoietic CD34(+) cells coexpressing mutated forms of RUNX1 and CSF3R. The high frequency of cooperating RUNX1 and CSF3R mutations in CN patients suggests a novel molecular pathway of leukemogenesis: mutations in the hematopoietic cytokine receptor (G-CSFR) in combination with the second mutations in the downstream hematopoietic transcription fator (RUNX1). The detection of both RUNX1 and CSF3R mutations could be used as a marker for identifying CN patients with a high risk of progressing to leukemia or MDS.
Assuntos
Transformação Celular Neoplásica/genética , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Leucemia Mieloide/genética , Mutação , Neutropenia/congênito , Receptores de Fator Estimulador de Colônias/genética , Adolescente , Adulto , Criança , Pré-Escolar , Síndrome Congênita de Insuficiência da Medula Óssea , Análise Citogenética , Feminino , Humanos , Masculino , Neutropenia/genética , Neutropenia/patologia , Transdução de Sinais/genética , Adulto JovemAssuntos
Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/genética , Mutação , Síndromes Mielodisplásicas/genética , Fatores de Processamento de RNA/genética , Adulto , Fatores Etários , Criança , Cromatina/genética , Metilação de DNA/genética , Humanos , Pessoa de Meia-Idade , Transcrição Gênica/genética , CoesinasRESUMO
Severe congenital neutropenia (SCN) patients treated with CSF3/G-CSF to alleviate neutropenia frequently develop acute myeloid leukemia (AML). A common pattern of leukemic transformation involves the appearance of hematopoietic clones with CSF3 receptor (CSF3R) mutations in the neutropenic phase, followed by mutations in RUNX1 before AML becomes overt. To investigate how the combination of CSF3 therapy and CSF3R and RUNX1 mutations contributes to AML development, we make use of mouse models, SCN-derived induced pluripotent stem cells (iPSCs), and SCN and SCN-AML patient samples. CSF3 provokes a hyper-proliferative state in CSF3R/RUNX1 mutant hematopoietic progenitors but does not cause overt AML. Intriguingly, an additional acquired driver mutation in Cxxc4 causes elevated CXXC4 and reduced TET2 protein levels in murine AML samples. Expression of multiple pro-inflammatory pathways is elevated in mouse AML and human SCN-AML, suggesting that inflammation driven by downregulation of TET2 activity is a critical step in the malignant transformation of SCN.