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Haematologica. 2019 Jan 10. pii: haematol.2018.204974. doi: 10.3324/haematol.2018.204974. [Epub ahead of print]

Genomic landscape of pediatric B-other acute lymphoblastic leukemia in a consecutive European cohort.

Author information

1
Dept. of Paediatric Haematology/Oncology, Second Faculty of Medicine, Charles University, Prague, CZ.
2
Dept. of Paediatric Haematology/Oncology, Second Faculty of Medicine, Charles University, Prague, CZ jan.trka@lfmotol.cuni.cz.

Abstract

Novel biological subtypes and clinically important genetic aberrations (druggable lesions, prognostic factors) have been described in B-other acute lymphoblastic leukemia during the last decade; however, due to a lack of studies on unselected cohorts, their population frequency and mutual associations remain to be established. We studied 110 consecutively diagnosed and uniformly treated childhood B-other patients using single nucleotide polymorphism arrays and whole exome/transcriptome sequencing. The frequency of DUX4-rearranged, BCR-ABL1-like, ZNF384-rearranged, ETV6-RUNX1-like, iAMP21 and MEF2D-rearranged subtypes was 27%, 15%, 5%, 5%, 4% and 2%, respectively; 43% of cases were not classified into any of these subtypes (B-rest). We found worse early response to treatment in DUX4-rearranged leukemia and a strong association of ZNF384-rearranged leukemia with B-myeloid immunophenotype. Of druggable lesions, JAK/STAT-class and RAS/RAF/MAPK-class aberrations were found in 21% and 43% of patients, respectively; an ABL-class aberration was found in a single patient. A recently described negative prognostic factor, IKZF1plus, was found in 14% of patients and was enriched in (but not exclusive for) BCR-ABL1-like subtype. PAX5 fusions (including 4 novel), intragenic amplifications and P80R mutations were mutually exclusive and occurred exclusively in B-rest subset, altogether accounting for 20% of B-other group. PAX5 P80R was associated with a specific gene expression signature potentially defining a novel leukemia subtype. Our study shows unbiased European population-based frequencies of novel ALL subtypes, recurrent (cyto)genetic aberrations and their mutual associations; this study also strengthens and widens the current knowledge of B-other acute lymphoblastic leukemia and provides an objective basis for optimization of current genetic diagnostics.

KEYWORDS:

B-other ALL; IKZF1plus; PAX5 P80R; Pediatric Acute Lymphoblastic Leukemia; kinase-activating lesions

PMID:
30630978
DOI:
10.3324/haematol.2018.204974
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