Constructive role of dissipation for driven coupled bosonic modes

We describe four cases of childhood B-cell progenitor acute lymphoblastic leukaemia (BCP-ALL) and one of T-cell (T-ALL) with unexpected numbers of interphase signals for ETV6 with an ETV6-RUNX1 fusion probe. Three fusion negative cases each had a telomeric part of 12p terminating within intron 2 of ETV6, attached to sequences from 5q, 7p and 7q, respectively. Two fusion positive cases, with partial insertions of ETV6 into chromosome 21, also had a breakpoint in intron 2. Fluorescence in situ hybridisation ( FISH), array comparative genomic hybridization (aCGH) and Molecular Copy-Number Counting (MCC) results were concordant for the T-cell case. Sequences downstream of TLX3 on chromosome 5 were deleted, leaving the intact gene closely apposed to the first two exons of ETV6 and its upstream promoter. qRT-PCR showed a significant upregulation of TLX3. In this study we provide the first incontrovertible evidence that the upstream promoter of ETV6 attached to the first two exons of the gene was responsible for the ectopic expression of a proto-oncogene that became abnormally close as the result of deletion and translocation. We have also shown breakpoints in intron 2 of ETV6 in two cases of insertion with ETV6-RUNX1 fusion

Detection of t(7;12)(q36;p13) in paediatric leukaemia using dual colour fluorescence in situ hybridisation

The identification of chromosomal rearrangements is of utmost importance for the diagnosis and classification of specific leukaemia subtypes and therefore has an impact on therapy choices in individual cases. The t(7;12)(q36;p13) is a cryptic rearrangement that is difficult to recognise using conventional cytogenetic methods and is often undetected by reverse transcription polymerase chain reaction due to the absence of a fusion transcript in many cases. Here we present a reliable and easy to use dual colour fluorescence in situ hybridisation assay for the detection of the t(7;12)(q36;p13) rearrangement. A comparison with previous similar work is given and advantages and limitations of this novel approach are discussed

A novel three-colour fluorescence in situ hybridization approach for the detection of t(7;12)(q36;p13) in acute myeloid leukaemia reveals new cryptic three way translocation t(7;12;16)

© 2013 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/).The t(7;12)(q36;p13) translocation is a recurrent chromosome abnormality that involves the ETV6 gene on chromosome 12 and has been identified in 20–30% of infant patients with acute myeloid leukaemia (AML). The detection of t(7;12) rearrangements relies on the use of fluorescence in situ hybridization (FISH) because this translocation is hardly visible by chromosome banding methods. Furthermore, a fusion transcript HLXB9-ETV6 is found in approximately 50% of t(7;12) cases, making the reverse transcription PCR approach not an ideal screening method. Considering the report of few cases of variant translocations harbouring a cryptic t(7;12) rearrangement, we believe that the actual incidence of this abnormality is higher than reported to date. The clinical outcome of t(7;12) patients is believed to be poor, therefore an early and accurate diagnosis is important in the clinical management and treatment. In this study, we have designed and tested a novel three-colour FISH approach that enabled us not only to confirm the presence of the t(7;12) in a number of patients studied previously, but also to identify a cryptic t(7;12) as part of a complex rearrangement. This new approach has proven to be an efficient and reliable method to be used in the diagnostic setting

Novel strategy for rapid functional in vivo validation of oncogenic drivers in haematological malignancies

In cancer research, it remains challenging to functionally validate putative novel oncogenic drivers and to establish relevant preclinical models for evaluation of novel therapeutic strategies. Here, we describe an optimized and efficient pipeline for the generation of novel conditional overexpression mouse models in which putative oncogenes, along with an eGFP/Luciferase dual reporter, are expressed from the endogenous ROSA26 (R26) promoter. The efficiency of this approach was demonstrated by the generation and validation of novel R26 knock-in (KI) mice that allow conditional overexpression of Jarid2, Runx2, MN1 and a dominant negative allele of ETV6. As proof of concept, we confirm that MN1 overexpression in the hematopoietic lineage is sufficient to drive myeloid leukemia. In addition, we show that T-cell specific activation of MN1 in combination with loss of Pten increases tumour penetrance and stimulates the formation of Lyl1(+) murine T-cell lymphoblastic leukemias or lymphomas (T-ALL/T-LBL). Finally, we demonstrate that these luciferase-positive murine AML and T-ALL/T-LBL cells are transplantable into immunocompromised mice allowing preclinical evaluation of novel antileukemic drugs in vivo

The molecular basis of T cell acute lymphoblastic leukemia

T cell acute lymphoblastic leukemias (T-ALLs) arise from the malignant transformation of hematopoietic progenitors primed toward T cell development, as result of a multistep oncogenic process involving constitutive activation of NOTCH signaling and genetic alterations in transcription factors, signaling oncogenes, and tumor suppressors. Notably, these genetic alterations define distinct molecular groups of T-ALL with specific gene expression signatures and clinicobiological features. This review summarizes recent advances in our understanding of the molecular genetics of T-ALL

Pediatric Cancers: Development and Treatment Methods

Pediatric cancers are cancers that develop in kids and adolescents ages 0-19. Pediatric cancers usually develop in three ways: through inherited gene mutations, parental exposure to toxins, and acquired gene mutations. While cancer can affect children and adults alike, treatment becomes more difficult for children due to their physical predevelopment stages. Therefore, it is important to discuss all methods of treatment when dealing with a particular pediatric cancer in order to choose the most effective method

Fusion of the homeobox gene HLXB9 and the ETV6 gene in infant acute myeloid leukemias with the t(7;12)(q36;p13)

Recently, we and others reported a recurrent t(7;12)(q36;p13) found in myeloid malignancies in children < or =18 months of age and associated with a poor prognosis. Fluorescence in situ hybridization studies mapped the 12p13 breakpoint to the first intron of ETV6 and narrowed down the region of 7q36 involved. By using the sequences made public recently by the Human Genome Project, two candidate genes in 7q36 were identified: the homeobox gene HLXB9 and c7orf3, a gene with unknown function. Reverse transcription-PCR of two cases with t(7;12), using primers for c7orf3 and ETV6, was negative. However, reverse transcription-PCR for HLXB9-ETV6 demonstrated alternative splicing; the two major bands corresponded to fusion of exon 1 of HLXB9 to exons 2 and 3, respectively, of ETV6. The reciprocal ETV6-HLXB9 transcript was not detected. It remains to be elucidated if the leukemic phenotype is attributable to the formation of the HLXB9-ETV6 fusion protein, which includes the helix-loop-helix and E26 transformation-specific DNA binding domains of ETV6 or to the disruption of the normal ETV6 protein

Dynamic clonal progression in xenografts of acute lymphoblastic leukemia with intrachromosomal amplification of chromosome 21

Intrachromosomal amplification of chromosome 21 is a heterogeneous chromosomal rearrangement occurring in 2% of childhood precursor B-cell acute lymphoblastic leukemia. There are no cell lines with iAMP21 and these abnormalities are too complex to faithfully engineer in animal models. As a resource for future functional and pre-clinical studies, we have created xenografts from intrachromosomal amplification of chromosome 21 leukemia patient blasts and characterised them by in-vivo and ex-vivo luminescent imaging, FLOW immunophenotyping, and histological and ultrastructural analysis of bone marrow and the central nervous system. Investigation of up to three generations of xenografts revealed phenotypic evolution, branching genomic architecture and, compared with other B-cell acute lymphoblastic leukemia genetic subtypes, greater clonal diversity of leukemia initiating cells. In support of intrachromosomal amplification of chromosome 21 as a primary genetic abnormality, it was always retained through generations of xenografts, although we also observed the first example of structural evolution of this rearrangement. Clonal segregation in xenografts revealed convergent evolution of different secondary genomic abnormalities implicating several known tumour suppressor genes and a region, containing the B-cell adaptor, PIK3AP1, and nuclear receptor co-repressor, LCOR, in the progression of B-ALL. Tracking of mutations in patients and derived xenografts provided evidence for co-operation between abnormalities activating the RAS pathway in B-ALL and for their aggressive clonal expansion in the xeno-environment. Bi-allelic loss of the CDKN2A/B locus was recurrently maintained or emergent in xenografts and also strongly selected as RNA sequencing demonstrated a complete absence of reads for genes associated with the deletions