Constitutional polymorphisms in ARID5B are associated with an increased risk of developing high hyperdiploid (HeH; 51-67 chromosomes) pediatric B-cell precursor acute lymphoblastic leukemia (BCP ALL). Here, we investigated constitutional and somatic ARID5B variants in 1335 BCP ALL cases from five different cohorts, with a particular focus on HeH cases. In 353 HeH ALL that were heterozygous for risk alleles and trisomic for chromosome 10, where ARID5B is located, a significantly higher proportion of risk allele duplication was seen for the SNPs rs7090445 (p = 0.009), rs7089424 (p = 0.005), rs7073837 (p = 0.03), and rs10740055 (p = 0.04). Somatic ARID5B deletions were seen in 16/1335 cases (1.2%), being more common in HeH than in other genetic subtypes (2.2% vs. 0.4%; p = 0.002). The expression of ARID5B in HeH cases with genomic deletions was reduced, consistent with a functional role in leukemogenesis. Whole-genome sequencing and RNA-sequencing in HeH revealed additional somatic events involving ARID5B, resulting in a total frequency of 3.6% of HeH cases displaying a somatic ARID5B aberration. Overall, our results show that both constitutional and somatic events in ARID5B are involved in the leukemogenesis of pediatric BCP ALL, particularly in the HeH subtype.

• MeSH
• dítě MeSH
• DNA vazebné proteiny * genetika   MeSH
• jednonukleotidový polymorfismus MeSH
• lidé MeSH
• pre-B-buněčná leukemie * genetika   MeSH
• předškolní dítě MeSH
• transkripční faktory * genetika   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

• MeSH
• akutní lymfatická leukemie * genetika   diagnóza   MeSH
• chromozomální aberace * MeSH
• lidé středního věku MeSH
• lidé MeSH
• senioři MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• dopisy MeSH

High hyperdiploid acute lymphoblastic leukemia (HeH ALL), one of the most common childhood malignancies, is driven by nonrandom aneuploidy (abnormal chromosome numbers) mainly comprising chromosomal gains. In this study, we investigate how aneuploidy in HeH ALL arises. Single cell whole genome sequencing of 2847 cells from nine primary cases and one normal bone marrow reveals that HeH ALL generally display low chromosomal heterogeneity, indicating that they are not characterized by chromosomal instability and showing that aneuploidy-driven malignancies are not necessarily chromosomally heterogeneous. Furthermore, most chromosomal gains are present in all leukemic cells, suggesting that they arose early during leukemogenesis. Copy number data from 577 primary cases reveals selective pressures that were used for in silico modeling of aneuploidy development. This shows that the aneuploidy in HeH ALL likely arises by an initial tripolar mitosis in a diploid cell followed by clonal evolution, in line with a punctuated evolution model.

• MeSH
• akutní lymfatická leukemie * genetika   MeSH
• aneuploidie * MeSH
• chromozomální aberace MeSH
• chromozomální nestabilita MeSH
• diploidie MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Mutations in the FMS-like tyrosine kinase 3 (FLT3) gene in 13q12.2 are among the most common driver events in acute leukemia, leading to increased cell proliferation and survival through activation of the phosphatidylinositol 3-kinase/AKT-, RAS/MAPK-, and STAT5-signaling pathways. In this study, we examine the pathogenetic impact of somatic hemizygous 13q12.2 microdeletions in B-cell precursor (BCP) acute lymphoblastic leukemia (ALL) using 5 different patient cohorts (in total including 1418 cases). The 13q12.2 deletions occur immediately 5' of FLT3 and involve the PAN3 locus. By detailed analysis of the 13q12.2 segment, we show that the deletions lead to loss of a topologically associating domain border and an enhancer of FLT3. This results in increased cis interactions between the FLT3 promoter and another enhancer located distally to the deletion breakpoints, with subsequent allele-specific upregulation of FLT3 expression, expected to lead to ligand-independent activation of the receptor and downstream signaling. The 13q12.2 deletions are highly enriched in the high-hyperdiploid BCP ALL subtype (frequency 3.9% vs 0.5% in other BCP ALL) and in cases that subsequently relapsed. Taken together, our study describes a novel mechanism of FLT3 involvement in leukemogenesis by upregulation via chromatin remodeling and enhancer hijacking. These data further emphasize the role of FLT3 as a driver gene in BCP ALL.

• MeSH
• akutní lymfatická leukemie genetika   MeSH
• buněčné linie MeSH
• chromozomální delece MeSH
• chromozomální poruchy komplikace   genetika   MeSH
• jednonukleotidový polymorfismus MeSH
• kohortové studie MeSH
• lidé MeSH
• lidské chromozomy, pár 13 genetika   MeSH
• mikročipová analýza MeSH
• regulace genové exprese u leukemie MeSH
• restrukturace chromatinu genetika   fyziologie   MeSH
• sekvenování celého genomu MeSH
• sekvenování transkriptomu MeSH
• tyrosinkinasa 3 podobná fms genetika   MeSH
• upregulace genetika   MeSH
• variabilita počtu kopií segmentů DNA genetika   MeSH
• zesilovače transkripce genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH