scholarly journals Mitotic crossover promotes leukemogenesis in children born with TEL-AML1 via the generation of loss of heterozygosity at 12p

2015 ◽  
Vol 37 (2) ◽  
Author(s):  
Ivan Ivanovski ◽  
Livia Garavelli ◽  
Olivera Djurić ◽  
Aleksandar Ćirović ◽  
Dejan Škorić ◽  
...  

TEL-AML1 (ETV6-RUNX1) fusion gene which is formed prenatally in 1% of the newborns, is a common genetic abnormality in childhood Bcell precursor acute lymphoblastic leukemia. But only one child out of a hundred children born with this fusion gene develops leukemia (bottleneck phenomenon) later in its life, if contracts the second mutation. In other words, out of a hundred children born with TEL-AML1 only one child is at risk for leukemia development, which means that TEL-AML1 fusion gene is not sufficient for overt leukemia. There is a stringent requirement for a second genetic abnormality for leukemia development and this is the real or the ultimate cause of the leukemia <em>bottleneck</em> phenomenon. In most cases of TEL-AML1<sup>+</sup> leukemia, the translocation t(12;21) is complemented with the loss of the normal TEL gene, not involved in the translocation, on the contralateral 12p. The loss of the normal TEL gene, <em>i.e.</em> loss of heterozygosity at 12p, occurs postnatally during the mitotic proliferation of TEL-AML1<sup>+</sup> cell in the mitotic crossing over process. Mitotic crossing over is a very rare event with a frequency rate of 10<sup>–6</sup> in a 10 kb region. The exploration and identification of the environmental exposure(s) that cause(s) proliferation of the TELAML1<sup>+</sup> cell in which approximately 10<sup>6</sup> mitoses are generated to cause 12p loss of heterozygosity, <em>i.e.</em> TEL gene deletion, may contribute to the introduction of preventive measures for leukemia.

2018 ◽  
Vol 25 (24) ◽  
pp. 2811-2825 ◽  
Author(s):  
Raffaella Franca ◽  
Natasa K. Kuzelicki ◽  
Claudio Sorio ◽  
Eleonora Toffoletti ◽  
Oksana Montecchini ◽  
...  

Acute lymphoblastic leukemia (ALL) is the most common hematologic malignancy in children, characterized by an abnormal proliferation of immature lymphoid cells. Thanks to risk-adapted combination chemotherapy treatments currently used, survival at 5 years has reached 90%. ALL is a heterogeneous disease from a genetic point of view: patients’ lymphoblasts may harbor in fact several chromosomal alterations, some of which have prognostic and therapeutic value. Of particular importance is the translocation t(9;22)(q34;q11.2) that leads to the formation of the BCR-ABL1 fusion gene, encoding a constitutively active chimeric tyrosine kinase (TK): BCR-ABL1 that is present in ~3% of pediatric ALL patients with B-immunophenotype and is associated with a poor outcome. This type of ALL is potentially treatable with specific TK inhibitors, such as imatinib. Recent studies have demonstrated the existence of a subset of BCR-ABL1 like leukemias (~10-15% of Bimmunophenotype ALL), whose blast cells have a gene expression profile similar to that of BCR-ABL1 despite the absence of t(9;22)(q34;q11.2). The precise pathogenesis of BCR-ABL1 like ALL is still to be defined, but they are mainly characterized by the activation of constitutive signal transduction pathways due to chimeric TKs different from BCR-ABL1. BCR-ABL1 like ALL patients represent a group with unfavorable outcome and are not identified by current risk criteria. In this review, we will discuss the design of targeted therapy for patients with BCR-ABL1 like ALL, which could consider TK inhibitors, and discuss innovative approaches suitable to identify the presence of patient’s specific chimeric TK fusion genes, such as targeted locus amplification or proteomic biosensors.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Xiang Zhang ◽  
Xuewu Zhang ◽  
Xia Li ◽  
Yunfei Lv ◽  
Yanan Zhu ◽  
...  

Abstract IKZF1 belongs to the IKAROS family of transcription factors, and its deletion/mutation frequently affects acute lymphoblastic leukemia. In acute myeloid leukemia, IKZF1 deletion has been demonstrated recurrent, but whether IKZF1 mutation also exists in AML remained largely unknown. Herein, we analyzed the IKZF1 mutation in AML. In our cohort, the frequency of IKZF1 mutation was 2.6% (5/193), and 5 frameshift/nonsense mutations as well as 2 missense mutations were identified in total. Molecularly, IKZF1 mutation was absent in fusion gene-positive AML, but it was demonstrated as the significant concomitant genetic alteration with SF3B1 or bi-alleleCEBPA mutation in AML. Clinically, two IKZF1, PTPN11 and SF3B1-mutated AML patients exhibited one aggressive clinical course and showed primary resistant to chemotherapy. Furthermore, we confirmed the recurrent IKZF1 mutation in AML with cBioPortal tool from OHSU, TCGA and TARGET studies. Interestingly, OHSU study also showed that SF3B1 mutation was the significant concomitant genetic alteration with IKZF1 mutation, indicating their strong synergy in leukemogenesis. In conclusion, IKZF1 mutation recurrently affected AML.


Blood ◽  
2015 ◽  
Vol 125 (23) ◽  
pp. 3609-3617 ◽  
Author(s):  
Jinjun Dang ◽  
Lei Wei ◽  
Jeroen de Ridder ◽  
Xiaoping Su ◽  
Alistair G. Rust ◽  
...  

Key Points Heterozygous alterations of Pax5, the most common target of genetic alteration in ALL, promote ALL in mouse mutagenesis models. Leukemia development is accompanied by the acquisition of genetic alterations commonly observed in human leukemia.


2003 ◽  
Vol 37 (1) ◽  
pp. 106-109 ◽  
Author(s):  
Jochen Bruch ◽  
Monika Wilda ◽  
Andrea Teigler-Schlegel ◽  
Jochen Harbott ◽  
Arndt Borkhardt ◽  
...  

Leukemia ◽  
2008 ◽  
Vol 23 (1) ◽  
pp. 125-133 ◽  
Author(s):  
C Graux ◽  
◽  
M Stevens-Kroef ◽  
M Lafage ◽  
N Dastugue ◽  
...  

Haematologica ◽  
2019 ◽  
Vol 104 (10) ◽  
pp. e455-e459 ◽  
Author(s):  
Femke M. Hormann ◽  
Alex Q. Hoogkamer ◽  
H. Berna Beverloo ◽  
Aurélie Boeree ◽  
Ilse Dingjan ◽  
...  

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