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Sequential and hierarchical chromosomal changes and chromosome instability are distinct features of high hyperdiploid pediatric acute lymphoblastic leukemia
Author(s) -
Alpár Donát,
Pajor Gábor,
Varga Péter,
Kajtár Béla,
Pótó László,
Mátics Róbert,
Vojcek Ágnes,
Ottoffy Gábor,
Szuhai Károly,
Pajor László
Publication year - 2014
Publication title -
pediatric blood and cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.116
H-Index - 105
eISSN - 1545-5017
pISSN - 1545-5009
DOI - 10.1002/pbc.25217
Subject(s) - chromosome instability , chromosome , genome instability , fluorescence in situ hybridization , karyotype , biology , aneuploidy , genetics , chromothripsis , cancer research , leukemia , marker chromosome , chromosome regions , cytogenetics , mitosis , gene , dna , dna damage
Background Pathogenesis of the non‐random accumulation of extra chromosomes in the low and high hyperdiploid (HeL, HeH) pre‐B pediatric acute lymphoblastic leukemia (B‐pALL) is largely unknown, and has been clarified with respect only to tetrasomic chromosomes. We analyzed the hierarchy of changes in chromosome number and chromosomal instability, as well as clonal heterogeneity and evolution, in the untreated bone marrow cell samples from 214 B‐pALL patients. Procedure Applying relocation, 2 × 4 color interphase fluorescence in situ hybridization was used to detect copy number alterations (CNAs) of the most commonly involved chromosomes, 4, 6, 10, 14, 17, 18, 21, and X. This approach allowed us to acquire a dataset correlated for all eight parameters. Results Based on chromosome number, an average of 6.9 and 10.2, whereas according to unique constellation 15.3 and 26.7 subclones could be identified in the HeL and HeH subgroups, respectively. Cluster analysis revealed the order of CNAs to chromosomes was highly conserved, and network analysis indicated changes in chromosome number were sequential for 80–90% of all numerical aberrations. Significant chromosome instability was revealed in both subgroups of leukemia. Conclusions Data generated using this new approach indicate that chromosomal instability, which causes heterogeneity in the subclonal landscape, and the sequential changes to chromosome numbers, are both determining factors in the pathomechanism of the hyperdiploid B‐pALL. These new observations could prompt research into the mitotic machinery of leukemic cells to identify new therapeutic targets for treating this disease. Pediatr Blood Cancer 2014;61:2208–2214. © 2014 Wiley Periodicals, Inc.