RESUMO
Although 90% of children with acute lymphoblastic leukemia (ALL) are now cured, the prognosis for infant-ALL remains dismal. Infant-ALL is usually caused by a single genetic hit that arises in utero: an MLL/KMT2A gene rearrangement (MLL-r). This is sufficient to induce a uniquely aggressive and treatment-refractory leukemia compared to older children. The reasons for disparate outcomes in patients of different ages with identical driver mutations are unknown. Using the most common MLL-r in infant-ALL, MLL-AF4, as a disease model, we show that fetal-specific gene expression programs are maintained in MLL-AF4 infant-ALL but not in MLL-AF4 childhood-ALL. We use CRISPR-Cas9 gene editing of primary human fetal liver hematopoietic cells to produce a t(4;11)/MLL-AF4 translocation, which replicates the clinical features of infant-ALL and drives infant-ALL-specific and fetal-specific gene expression programs. These data support the hypothesis that fetal-specific gene expression programs cooperate with MLL-AF4 to initiate and maintain the distinct biology of infant-ALL.
Assuntos
Feto , Regulação Neoplásica da Expressão Gênica , Proteína de Leucina Linfoide-Mieloide/genética , Proteínas de Fusão Oncogênica/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Animais , Sistemas CRISPR-Cas , Proteínas de Ligação a DNA , Feminino , Edição de Genes , Histona-Lisina N-Metiltransferase , Humanos , Fígado , Camundongos , Proteína de Leucina Linfoide-Mieloide/metabolismo , Proteínas de Fusão Oncogênica/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Fatores de Elongação da TranscriçãoRESUMO
In this study, we report three paediatric cases of Diffuse Glioneuronal Tumours with Oligodendroglioma-like features and Nuclear Clusters (DGONC).
Assuntos
Neoplasias Encefálicas/patologia , Ganglioglioma/patologia , Oligodendroglioma/patologia , Criança , Humanos , MasculinoRESUMO
Here, we report a high incidence of PAX5 abnormalities observed in 32/68 (47%) of patients with genetically unclassified childhood precursor B-cell acute lymphoblastic leukaemia (pre-B ALL). Various deletions, gains, mutations and rearrangements of PAX5 comprised 45%, 12%, 29% and 14%, respectively, of the abnormalities found. 28% of patients showed more than one abnormality of the gene, implying bi-allelic impairment of PAX5. Novel PAX5-RHOXF2, PAX5-ELK3 and PAX5-CBFA2T2 rearrangements, which lead to aberrant expression of PAX5, were also identified. PAX5 rearrangements demonstrated a complex mechanism of formation including concurrent duplications/deletions of PAX5 and its partner genes. Finally, the splice variant c.1013-2A>G, seen in two patients with loss of one PAX5 allele, was confirmed to be germ-line in one patient and somatic in the other. PAX5 alterations were also found to be clinically associated with a higher white blood cell count (P = 0·015). These findings contribute to the knowledge of PAX5 alterations and their role in the pathogenesis of pre-B ALL.
