ETV6

Gene Summary

Gene:ETV6; ets variant 6
Aliases: TEL, THC5, TEL/ABL
Location:12p13
Summary:This gene encodes an ETS family transcription factor. The product of this gene contains two functional domains: a N-terminal pointed (PNT) domain that is involved in protein-protein interactions with itself and other proteins, and a C-terminal DNA-binding domain. Gene knockout studies in mice suggest that it is required for hematopoiesis and maintenance of the developing vascular network. This gene is known to be involved in a large number of chromosomal rearrangements associated with leukemia and congenital fibrosarcoma. [provided by RefSeq, Sep 2008]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:transcription factor ETV6
HPRD
Source:NCBIAccessed: 17 March, 2015

Ontology:

What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
Show (1)

Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 17 March 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 17 March, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (13)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Entity Topic PubMed Papers
Acute Lymphocytic Leukemia (ALL), childt(12;21) in Childhood Acute Lymphoblastic Leukaemia
The t(12;21)(p13;q22), RUNX1-ETV6 (TEL-AML1) translocation, is observed in approximately 20-25% of childhood B-lineage acute lymphoblastic leukemia (ALL) cases in both Asian and Caucasian populations (Kobayashi et al, 1997). It is the most frequent known genetic abnormality in childhood B-cell ALL.
View Publications230
Acute Myeloid Leukaemia (AML)ETV6 and Acute Myeloid Leukaemia View Publications53
Acute Lymphocytic Leukaemia (ALL)t(12;21) in Adult Lyphocytic Leukaemia
The t(12;21)(p13;q22), RUNX1-ETV6 (TEL-AML1) translocation, is observed in aproximately 3% of adult acute lymphoblastic leukaemias (ALL) while it occurs in about a quarter of childhood B-cell ALL cases (Aguiar et al, 1996 and Kwong et al 1999).
View Publications35
Leukaemiat(9;12)(p24;p13) ETV6-JAK2 fusion in lymphoid and myeloid leukemia View Publications33
Salivary Gland CancerETV6 and Salivary Gland Cancer View Publications25
Acute Lymphocytic Leukaemia (ALL)t(1;12)(q25;p13) in Leukaemia (AML & ALL)
The ETV6 (TEL) gene is frequently rearranged to various translocation partners in human leukemias. In a small number of cases the ETV6 gene is translocated with the ABL2 gene. In a RT-PCR study of samples from 176 patients with acute lymphoblastic leukemia (Zhou et al, 2012) found 15 had ETV6 gene rearrangements and of these 2 were ETV6/ABL1 translocations.
View Publications21
Soft Tissue Sarcoma, Childhoodt(12;15)(p13;q25) ETV6-NTRK3 in Congenital Fibrosarcoma
The t(12;15)(p13;q25) fusing the ETV6 and NTRK3 genes has been reported in congenital (infantile) fibrosarcoma. In an RT-PCR study of paediatric tumours (Bourgeois, 2000), the ETV6-NTRK3 fusion transcripts were detected in 10/11 congenital fibrosarcomas compared to 0/13 other malignant spindle cell tumours and 0/38 benign spindle cell tumours. The authors suggest RT-PCR assays to detect the ETV6-NTRK3 gene fusion will be useful in the diagnosis of congenital fibrosarcoma and in particular to differentiation from more aggressive spindle cell sarcomas including adult-type fibrosarcoma.
View Publications20
Soft Tissue SarcomaETV6 and Soft Tissue Cancers View Publications17
-t(12;15)(p13;q25) ETV6-NTRK3 in congenital mesoblastic nephroma View Publications7
Breast Cancert(12;15)(p13;q25) ETV6-NTRK3 in Breast Cancer View Publications6
Testicular CancerETV6 and Testicular Cancer View Publications1
Leukaemiat(5;12)(q33;p13) in Chronic Myelomonocytic Leukemia
Chronic myelomonocytic leukaemia (CMML) is a myelodysplastic syndrome and is characterized dysplastic monocytosis, hypercellular bone marrow, splenomegaly, and progression to acute myelogenous leukemia (AML). A sub-set of CMMLs have a t(5;12)(q33;p13) balanced translocation involving the PDGFRB and ETV6 (TEL) genes.
View Publications1

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: ETV6 (cancer-related)

Roberts KG, Li Y, Payne-Turner D, et al.
Targetable kinase-activating lesions in Ph-like acute lymphoblastic leukemia.
N Engl J Med. 2014; 371(11):1005-15 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) is characterized by a gene-expression profile similar to that of BCR-ABL1-positive ALL, alterations of lymphoid transcription factor genes, and a poor outcome. The frequency and spectrum of genetic alterations in Ph-like ALL and its responsiveness to tyrosine kinase inhibition are undefined, especially in adolescents and adults.
METHODS: We performed genomic profiling of 1725 patients with precursor B-cell ALL and detailed genomic analysis of 154 patients with Ph-like ALL. We examined the functional effects of fusion proteins and the efficacy of tyrosine kinase inhibitors in mouse pre-B cells and xenografts of human Ph-like ALL.
RESULTS: Ph-like ALL increased in frequency from 10% among children with standard-risk ALL to 27% among young adults with ALL and was associated with a poor outcome. Kinase-activating alterations were identified in 91% of patients with Ph-like ALL; rearrangements involving ABL1, ABL2, CRLF2, CSF1R, EPOR, JAK2, NTRK3, PDGFRB, PTK2B, TSLP, or TYK2 and sequence mutations involving FLT3, IL7R, or SH2B3 were most common. Expression of ABL1, ABL2, CSF1R, JAK2, and PDGFRB fusions resulted in cytokine-independent proliferation and activation of phosphorylated STAT5. Cell lines and human leukemic cells expressing ABL1, ABL2, CSF1R, and PDGFRB fusions were sensitive in vitro to dasatinib, EPOR and JAK2 rearrangements were sensitive to ruxolitinib, and the ETV6-NTRK3 fusion was sensitive to crizotinib.
CONCLUSIONS: Ph-like ALL was found to be characterized by a range of genomic alterations that activate a limited number of signaling pathways, all of which may be amenable to inhibition with approved tyrosine kinase inhibitors. Trials identifying Ph-like ALL are needed to assess whether adding tyrosine kinase inhibitors to current therapy will improve the survival of patients with this type of leukemia. (Funded by the American Lebanese Syrian Associated Charities and others.).

Xie J, Wang Q, Wang Q, et al.
High frequency of BTG1 deletions in patients with BCR-ABL1-positive acute leukemia.
Cancer Genet. 2014; 207(5):226-30 [PubMed] Related Publications
Deletions affecting the B-cell translocation gene 1 (BTG1) have recently been reported in 9% of patients with B-cell precursor acute lymphoblastic leukemia (BCP-ALL), and occur even more frequently in ETV6-RUNX1-positive and BCR-ABL1-positive subgroups. To investigate whether the BTG1 deletions occur in other BCR-ABL1-positive acute leukemias besides BCP-ALL, we analyzed 44 leukemia cases harboring the BCR-ABL1 transcript [32 BCP-ALL, six mixed-phenotype acute leukemia (MPAL), and six chronic myeloid leukemia in B-lineage blast crisis (CML-BC)] by array-based comparative genomic hybridization and reverse transcription-PCR. BTG1 deletions were present in 31.8% of BCR-ABL1-positive acute leukemia patients, including 31.3% of BCP-ALL (10/32), 33.3% of MPAL (2/6), and 33.3% of CML-BC (B-lineage) (2/6) patients. Of note, the intragenic deletion breakpoints, mapping to 5 different positions at the proximal end of the breakpoint, clustered tightly within exon 2 of BTG1, which were located within a stretch of 20 bp from nucleotide 284 to nucleotide 304 and led to truncated BTG1 transcripts. There were no significant differences in the median white blood cell count, hemoglobin concentration, platelet count, bone marrow blast count, sex, age, or overall complete remission rate between patients with and without BTG1 deletions. Taken together, our data suggest that BTG1 deletions might play a role in leukemogenesis of BCP-ALL as well as of BCR-ABL1-positive MPAL and CML-BC (B-lineage).

Nieto MJ, Scalise A, Najfeld V
Cytogenetically normal acute myeloid leukemia with a novel KIT mutation in exon 11 G565V developing a sole trisomy 13 at relapse: a clinical dilemma.
Acta Haematol. 2015; 133(1):1-5 [PubMed] Related Publications
We describe a patient with acute myeloid leukemia (AML) who had a normal karyotype at diagnosis and was negative for NPM1 and FLT3 mutations, but had a KIT G565V mutation in exon 11. This has not been described previously in AML. The patient received induction and consolidation chemotherapy and was in hematologic remission for 351 days when deletion 7q was cytogenetically detected in 8% of the bone marrow cells. After an initial treatment of azacitidine followed by decitabine, an unrelated trisomy 13 clone was identified, followed by subclonal rearrangement of ETV6. The patient underwent reinduction with high-dose cytarabine and mitoxantrone followed by voluntary-unrelated-donor allogeneic stem cell transplantation with a reduced-intensity conditioning. As of writing, the patient is in complete hematologic and cytogenetic remission with 100% donor cell engraftment.

Bain BJ, Ahmad S
Should myeloid and lymphoid neoplasms with PCM1-JAK2 and other rearrangements of JAK2 be recognized as specific entities?
Br J Haematol. 2014; 166(6):809-17 [PubMed] Related Publications
Since the publication of the 2001 and 2008 World Health Organization classifications of tumours of haematopoietic and lymphoid tissues, there has been an increasing move towards classification of haematological neoplasms on the basis of the underlying molecular genetic disorder. In recent decades there have been a significant number of reports of haematological neoplasms with rearrangement of JAK2. Published data on such cases have therefore been analysed to determine if any specific entities could be identified. On the basis of this analysis, it is suggested that lymphoid and myeloid neoplasms associated with t(8;9)(p22;p24); PCM1-JAK2 fusion should be recognized as an entity. Furthermore, lymphoid and myeloid neoplasms associated respectively with t(9;12)(p24;p13); ETV6-JAK2 and with t(9;22)(p24;q11·2); BCR-JAK2 should be documented carefully in order to define their features more clearly and assess whether they can be recognized as entities. Identification of all these conditions is important because of the possibility of response to JAK2 inhibitors.

Dzikiewicz-Krawczyk A, Macieja A, Mały E, et al.
Polymorphisms in microRNA target sites modulate risk of lymphoblastic and myeloid leukemias and affect microRNA binding.
J Hematol Oncol. 2014; 7:43 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: MicroRNA dysregulation is a common event in leukemia. Polymorphisms in microRNA-binding sites (miRSNPs) in target genes may alter the strength of microRNA interaction with target transcripts thereby affecting protein levels. In this study we aimed at identifying miRSNPs associated with leukemia risk and assessing impact of these miRSNPs on miRNA binding to target transcripts.
METHODS: We analyzed with specialized algorithms the 3' untranslated regions of 137 leukemia-associated genes and identified 111 putative miRSNPs, of which 10 were chosen for further investigation. We genotyped patients with acute myeloid leukemia (AML, n = 87), chronic myeloid leukemia (CML, n = 140), childhood acute lymphoblastic leukemia (ALL, n = 101) and healthy controls (n = 471). Association between SNPs and leukemia risk was calculated by estimating odds ratios in the multivariate logistic regression analysis. For miRSNPs that were associated with leukemia risk we performed luciferase reporter assays to examine whether they influence miRNA binding.
RESULTS: Here we show that variant alleles of TLX1_rs2742038 and ETV6_rs1573613 were associated with increased risk of childhood ALL (OR (95% CI) = 3.97 (1.43-11.02) and 1.9 (1.16-3.11), respectively), while PML_rs9479 was associated with decreased ALL risk (OR = 0.55 (0.36-0.86). In adult myeloid leukemias we found significant associations between the variant allele of PML_rs9479 and decreased AML risk (OR = 0.61 (0.38-0.97), and between variant alleles of IRF8_ rs10514611 and ARHGAP26_rs187729 and increased CML risk (OR = 2.4 (1.12-5.15) and 1.63 (1.07-2.47), respectively). Moreover, we observed a significant trend for an increasing ALL and CML risk with the growing number of risk genotypes with OR = 13.91 (4.38-44.11) for carriers of ≥3 risk genotypes in ALL and OR = 4.9 (1.27-18.85) for carriers of 2 risk genotypes in CML. Luciferase reporter assays revealed that the C allele of ARHGAP26_rs187729 creates an illegitimate binding site for miR-18a-3p, while the A allele of PML_rs9479 enhances binding of miR-510-5p and the C allele of ETV6_rs1573613 weakens binding of miR-34c-5p and miR-449b-5p.
CONCLUSIONS: Our study implicates that microRNA-binding site polymorphisms modulate leukemia risk by interfering with the miRNA-mediated regulation. Our findings underscore the significance of variability in 3' untranslated regions in leukemia.

Parihar M, Gupta A, Remani AS, et al.
Novel t(2;12)(q31;p13) in a case of pediatric T-cell acute lymphoblastic leukemia.
J Pediatr Hematol Oncol. 2014; 36(5):e313-5 [PubMed] Related Publications
BACKGROUND: The role of ETV6 in B-cell acute lymphoblastic leukemia (ALL) has been extensively studied, whereas only rare cases of ETV6 involvement in pediatric T-cell ALL have been described.
OBSERVATION: We report a case of T-cell ALL in a 13-year-old boy with t(2;12)(q31;p13) involving ETV6, resulting in the relocation of the ETV6 from 12p13 to 2q31 locus that harbors the class 1 homeobox gene (HOX) cluster D, which is expressed during the early stages of T-cell development.
CONCLUSIONS: We report a novel translocation in T-cell ALL highlighting the involvement of ETV6 and potentially the HOXD gene cluster in a case of T-cell ALL.

Qadir MA, Zhan SH, Kwok B, et al.
ChildSeq-RNA: A next-generation sequencing-based diagnostic assay to identify known fusion transcripts in childhood sarcomas.
J Mol Diagn. 2014; 16(3):361-70 [PubMed] Related Publications
Childhood sarcomas can be extremely difficult to accurately diagnose on the basis of morphological characteristics alone. Ancillary methods, such as RT-PCR or fluorescence in situ hybridization, to detect pathognomonic gene fusions can help to distinguish these tumors. Two major deficiencies of these assays are their inability to identify gene fusions at nucleotide resolution or to detect multiple gene fusions simultaneously. We developed a next-generation sequencing-based assay designated ChildSeq-RNA that uses the Ion Torrent platform to screen for EWSR1-FLI1 and EWSR1-ERG, PAX3-FOXO1 and PAX7-FOXO1, EWSR1-WT1, and ETV6-NTRK3 fusions of Ewing sarcoma (ES), alveolar rhabdomyosarcoma, desmoplastic small round cell tumor, and congenital fibrosarcoma, respectively. To rapidly analyze resulting data, we codeveloped a bioinformatics tool, termed ChildDecode, that operates on a scalable, cloud-computing platform. Total RNA from four ES cell lines plus 33 clinical samples representing ES, alveolar rhabdomyosarcoma, desmoplastic small round cell tumor, and congenital fibrosarcoma tumors was subjected to ChildSeq-RNA. This accurately identified corresponding gene fusions in each tumor type, with no examples of false positive fusion detection in this proof-of-concept study. Comparison with previous RT-PCR findings demonstrated high sensitivity (96.4%; 95% CI, 82.3%-99.4%) and specificity (100%; 95% CI, 56.6%-100%) of ChildSeq-RNA to detect gene fusions. Herein, we propose ChildSeq-RNA as a novel tool to detect gene fusions in childhood sarcomas at single-nucleotide resolution.

Kuiper RP, Waanders E
A RAG driver on the road to pediatric ALL.
Nat Genet. 2014; 46(2):96-8 [PubMed] Related Publications
Genomic aberrations affecting genes in B cell differentiation are hallmarks of B-precursor acute lymphoblastic leukemia (ALL). A new whole-genome sequencing study of ETV6-RUNX1-positive ALL has now identified RAG-mediated recombination, which specifically targets genes and regulatory elements active during B cell differentiation, as the underlying mechanism.

Fortschegger K, Anderl S, Denk D, Strehl S
Functional heterogeneity of PAX5 chimeras reveals insight for leukemia development.
Mol Cancer Res. 2014; 12(4):595-606 [PubMed] Related Publications
UNLABELLED: PAX5, a transcription factor pivotal for B-cell commitment and maintenance, is one of the most frequent targets of somatic mutations in B-cell precursor acute lymphoblastic leukemia. A number of PAX5 rearrangements result in the expression of in-frame fusion genes encoding chimeric proteins, which at the N-terminus consistently retain the PAX5 DNA-binding paired domain fused to the C-terminal domains of a markedly heterogeneous group of fusion partners. PAX5 fusion proteins are thought to function as aberrant transcription factors, which antagonize wild-type PAX5 activity. To gain mechanistic insight into the role of PAX5 fusion proteins in leukemogenesis, the biochemical and functional properties of uncharacterized fusions: PAX5-DACH1, PAX5-DACH2, PAX5-ETV6, PAX5-HIPK1, and PAX5-POM121 were ascertained. Independent of the subcellular distribution of the wild-type partner proteins, ectopic expression of all PAX5 fusion proteins showed a predominant nuclear localization, and by chromatin immunoprecipitation all of the chimeric proteins exhibited binding to endogenous PAX5 target sequences. Furthermore, consistent with the presence of potential oligomerization motifs provided by the partner proteins, the self-interaction capability of several fusion proteins was confirmed. Remarkably, a subset of the PAX5 fusion proteins conferred CD79A promoter activity; however, in contrast with wild-type PAX5, the fusion proteins were unable to induce Cd79a transcription in a murine plasmacytoma cell line. These data show that leukemia-associated PAX5 fusion proteins share some dominating characteristics such as nuclear localization and DNA binding but also show distinctive features.
IMPLICATIONS: This comparative study of multiple PAX5 fusion proteins demonstrates both common and unique properties, which likely dictate their function and impact on leukemia development.

Papaemmanuil E, Rapado I, Li Y, et al.
RAG-mediated recombination is the predominant driver of oncogenic rearrangement in ETV6-RUNX1 acute lymphoblastic leukemia.
Nat Genet. 2014; 46(2):116-25 [PubMed] Free Access to Full Article Related Publications
The ETV6-RUNX1 fusion gene, found in 25% of childhood acute lymphoblastic leukemia (ALL) cases, is acquired in utero but requires additional somatic mutations for overt leukemia. We used exome and low-coverage whole-genome sequencing to characterize secondary events associated with leukemic transformation. RAG-mediated deletions emerge as the dominant mutational process, characterized by recombination signal sequence motifs near breakpoints, incorporation of non-templated sequence at junctions, ∼30-fold enrichment at promoters and enhancers of genes actively transcribed in B cell development and an unexpectedly high ratio of recurrent to non-recurrent structural variants. Single-cell tracking shows that this mechanism is active throughout leukemic evolution, with evidence of localized clustering and reiterated deletions. Integration of data on point mutations and rearrangements identifies ATF7IP and MGA as two new tumor-suppressor genes in ALL. Thus, a remarkably parsimonious mutational process transforms ETV6-RUNX1-positive lymphoblasts, targeting the promoters, enhancers and first exons of genes that normally regulate B cell differentiation.

Chatterton Z, Morenos L, Mechinaud F, et al.
Epigenetic deregulation in pediatric acute lymphoblastic leukemia.
Epigenetics. 2014; 9(3):459-67 [PubMed] Free Access to Full Article Related Publications
Similar to most cancers, genome-wide DNA methylation profiles are commonly altered in pediatric acute lymphoblastic leukemia (ALL); however, recent observations highlight that a large portion of malignancy-associated DNA methylation alterations are not accompanied by related gene expression changes. By analyzing and integrating the methylome and transcriptome profiles of pediatric B-cell ALL cases and primary tissue controls, we report 325 genes hypermethylated and downregulated and 45 genes hypomethylated and upregulated in pediatric B-cell ALL, irrespective of subtype. Repressed cation channel subunits and cAMP signaling activators and transducers are overrepresented, potentially indicating a reduced cellular potential to receive and propagate apoptotic signals. Furthermore, we report specific DNA methylation alterations with concurrent gene expression changes within individual ALL subtypes. The ETV6-RUNX1 translocation was associated with downregulation of ASNS and upregulation of the EPO-receptor, while Hyperdiploid patients (> 50 chr) displayed upregulation of B-cell lymphoma (BCL) members and repression of PTPRG and FHIT. In combination, these data indicate genetically distinct B-cell ALL subtypes contain cooperative epimutations and genome-wide epigenetic deregulation is common across all B-cell ALL subtypes.

Odejide O, Weigert O, Lane AA, et al.
A targeted mutational landscape of angioimmunoblastic T-cell lymphoma.
Blood. 2014; 123(9):1293-6 [PubMed] Free Access to Full Article Related Publications
The genetics of angioimmunoblastic T-cell lymphoma (AITL) are very poorly understood. We defined the mutational landscape of AITL across 219 genes in 85 cases from the United States and Europe. We identified ≥2 mutations in 34 genes, nearly all of which were not previously implicated in AITL. These included loss-of-function mutations in TP53 (n = 4), ETV6 (n = 3), CCND3 (n = 2), and EP300 (n = 5), as well as gain-of-function mutations in JAK2 (n = 2) and STAT3 (n = 4). TET2 was mutated in 65 (76%) AITLs, including 43 that harbored 2 or 3 TET2 mutations. DNMT3A mutations occurred in 28 (33%) AITLs; 100% of these also harbored TET2 mutations (P < .0001). Seventeen AITLs harbored IDH2 R172 substitutions, including 15 with TET2 mutations. In summary, AITL is characterized by high frequencies of overlapping mutations in epigenetic modifiers and targetable mutations in a subset of cases.

Leeman-Neill RJ, Kelly LM, Liu P, et al.
ETV6-NTRK3 is a common chromosomal rearrangement in radiation-associated thyroid cancer.
Cancer. 2014; 120(6):799-807 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: In their previous analysis of papillary thyroid carcinomas (PTCs) from an Ukrainian-American cohort that was exposed to iodine-131 ((131) I) from the Chernobyl accident, the authors identified RET/PTC rearrangements and other driver mutations in 60% of tumors.
METHODS: In this study, the remaining mutation-negative tumors from that cohort were analyzed using RNA sequencing (RNA-Seq) and reverse transcriptase-polymerase chain reaction to identify novel chromosomal rearrangements and to characterize their relation with radiation dose.
RESULTS: The ETS variant gene 6 (ETV6)-neurotrophin receptor 3 (NTRK3) rearrangement (ETV6-NTRK3) was identified by RNA-Seq in a tumor from a patient who received a high (131) I dose. Overall, the rearrangement was detected in 9 of 62 (14.5%) post-Chernobyl PTCs and in 3 of 151 (2%) sporadic PTCs (P = .019). The most common fusion type was between exon 4 of ETV6 and exon 14 of NTRK3. The prevalence of ETV6-NTRK3 rearrangement in post-Chernobyl PTCs was associated with increasing (131) I dose, albeit at borderline significance (P = .126). The group of rearrangement-positive PTCs (ETV6-NTRK3, RET/PTC, PAX8-PPARγ) was associated with significantly higher dose response compared with the group of PTCs with point mutations (BRAF, RAS; P < .001). In vitro exposure of human thyroid cells to 1 gray of (131) I and γ-radiation resulted in the formation of ETV6-NTRK3 rearrangement at a rate of 7.9 × 10(-6) cells and 3.0 × 10(-6) cells, respectively.
CONCLUSIONS: The authors report the occurrence of ETV6-NTRK3 rearrangements in thyroid cancer and demonstrate that this rearrangement is significantly more common in tumors associated with exposure to (131) I and has a borderline significant dose response. Moreover, ETV6-NTRK3 rearrangement can be directly induced in thyroid cells by ionizing radiation in vitro and, thus, may represent a novel mechanism of radiation-induced carcinogenesis.

Harrison CJ
Targeting signaling pathways in acute lymphoblastic leukemia: new insights.
Hematology Am Soc Hematol Educ Program. 2013; 2013:118-25 [PubMed] Related Publications
The genetics of acute lymphoblastic leukemia are becoming well understood and the incidence of individual chromosomal abnormalities varies considerably with age. Cytogenetics provide reliable risk stratification for treatment: high hyperdiploidy and ETV6-RUNX1 are good risk, whereas BCR-ABL1, MLL rearrangements, and hypodiploidy are poor risk. Nevertheless, some patients within the good- and intermediate-risk groups will unpredictably relapse. With advancing technologies in array-based approaches (single nucleotide polymorphism arrays) and next-generation sequencing to study the genome, increasing numbers of new genetic changes are being discovered. These include deletions of B-cell differentiation and cell cycle control genes, as well as mutations of genes in key signaling pathways. Their associations and interactions with established cytogenetic subgroups and with each other are becoming elucidated. Whether they have a link to outcome is the most important factor for refinement of risk factors in relation to clinical trials. For several newly identified abnormalities, including intrachromosomal amplification of chromosome 21 (iAMP21), that are associated with a poor prognosis with standard therapy, appropriately modified treatment has significantly improved outcome. After the successful use of tyrosine kinase inhibitors in the treatment of BCR-ABL1-positive acute lymphoblastic leukemia, patients with alternative ABL1 translocations and rearrangements involving PDGFRB may benefit from treatment with tyrosine kinase inhibitors. Other aberrations, for example, CRLF2 overexpression and JAK2 mutations, are also providing potential novel therapeutic targets with the prospect of reduced toxicity.

Kaindl U, Morak M, Portsmouth C, et al.
Blocking ETV6/RUNX1-induced MDM2 overexpression by Nutlin-3 reactivates p53 signaling in childhood leukemia.
Leukemia. 2014; 28(3):600-8 [PubMed] Free Access to Full Article Related Publications
ETV6/RUNX1 (E/R) is the most common fusion gene in childhood acute lymphoblastic leukemia. It is responsible for the initiation of leukemia but also indispensable for disease maintenance and propagation, although its function in these latter processes is less clear. We therefore investigated the effects of the perceived p53 pathway alterations in model cell lines and primary leukemias and, in particular, how E/R upregulates MDM2, the predominant negative regulator of p53. We found that E/R transactivates MDM2 in both p53(+/+) and p53(-/-) HCT116 cells by binding to promoter-inherent RUNX1 motifs, which indicates that this activation occurs in a direct and p53-independent manner. Treatment of E/R-positive leukemic cell lines with Nutlin-3, a small molecule that inhibits the MDM2/p53 interaction, arrests their cell cycle and induces apoptosis. These phenomena concur with a p53-induced expression of p21, pro-apoptotic BAX and PUMA, as well as caspase 3 activation and poly ADP-ribose polymerase cleavage. The addition of DNA-damaging and p53-activating chemotherapeutic drugs intensifies apoptosis. Moreover, Nutlin-3 exposure leads to an analogous p53 accumulation and apoptotic surge in E/R-positive primary leukemic cells. Our findings clarify the role of p53 signaling in E/R-positive leukemias and outline the potential basis for its therapeutic exploitation in this setting.

Kiyokawa N, Iijima K, Tomita O, et al.
Significance of CD66c expression in childhood acute lymphoblastic leukemia.
Leuk Res. 2014; 38(1):42-8 [PubMed] Related Publications
Upon analyzing 696 childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL) cases, we identified the characteristics of CD66c expression. In addition to the confirmation of strong correlation with BCR-ABL positivity and hyperdiploid, we further observed that CD66c is frequently expressed in CRLF2-positive (11/15, p<0.01 against chimeric gene-negative) as well as hypodiploid cases (3/4), whereas it is never expressed in ETV6-RUNX1, MLL-AF4, MLL-AF9, MLL-ENL, and E2A-PBX1-positive cases. Although the expression of CD66c itself is not directly linked to the prognosis, the accompanying genetic abnormalities are important prognostic factors for BCP-ALL, indicating the importance of CD66c expression in the initial diagnosis of BCP-ALL.

Harrison CJ, Moorman AV, Schwab C, et al.
An international study of intrachromosomal amplification of chromosome 21 (iAMP21): cytogenetic characterization and outcome.
Leukemia. 2014; 28(5):1015-21 [PubMed] Free Access to Full Article Related Publications
Intrachromosomal amplification of chromosome 21 (iAMP21) defines a distinct cytogenetic subgroup of childhood B-cell precursor acute lymphoblastic leukaemia (BCP-ALL). To date, fluorescence in situ hybridisation (FISH), with probes specific for the RUNX1 gene, provides the only reliable detection method (five or more RUNX1 signals per cell). Patients with iAMP21 are older (median age 9 years) with a low white cell count. Previously, we demonstrated a high relapse risk when these patients were treated as standard risk. Recent studies have shown improved outcome on intensive therapy. In view of these treatment implications, accurate identification is essential. Here we have studied the cytogenetics and outcome of 530 iAMP21 patients that highlighted the association of specific secondary chromosomal and genetic changes with iAMP21 to assist in diagnosis, including the gain of chromosome X, loss or deletion of chromosome 7, ETV6 and RB1 deletions. These iAMP21 patients when treated as high risk showed the same improved outcome as those in trial-based studies regardless of the backbone chemotherapy regimen given. This study reinforces the importance of intensified treatment to reduce the risk of relapse in iAMP21 patients. This now well-defined patient subgroup should be recognised by World Health Organisation (WHO) as a distinct entity of BCP-ALL.

Skálová A, Vanecek T, Majewska H, et al.
Mammary analogue secretory carcinoma of salivary glands with high-grade transformation: report of 3 cases with the ETV6-NTRK3 gene fusion and analysis of TP53, β-catenin, EGFR, and CCND1 genes.
Am J Surg Pathol. 2014; 38(1):23-33 [PubMed] Related Publications
Mammary analogue secretory carcinoma of salivary gland origin (MASC) is a recently described tumor resembling secretory carcinoma of the breast characterized by strong S-100 protein, mammaglobin, and vimentin immunoexpression and which harbors a t(12;15) (p13;q25) translocation resulting in ETV6-NTRK3 fusion product. Histologically, conventional MASC displays bland histomorphology and a lobulated growth pattern and is often composed of microcystic, tubular, and solid structures with abundant eosinophilic homogenous or bubbly secretions. Colloid-like secretory material stains positively for periodic acid-Schiff with and without diastase as well as for Alcian Blue. We present for the first time, 3 patients with MASC of the parotid gland in which high-grade (HG) transformation developed in each case characterized by an accelerated clinical course and poor outcome. The HG component revealed strong membrane staining for EGFR and β-catenin, cytoplasmic/nuclear staining for S-100 protein, and nuclear staining for cyclin-D1, whereas HER-2/neu was absent. Analysis for the presence of the ETV6-NTRK3 fusion transcript revealed positivity in both HG and low-grade component of MASC in 2 of the 3 studied cases. The tumor in case 2 was negative in both its elements for the t(12;15) translocation, but ETV6 gene rearrangement was detected in both components in all 3 cases. Analysis of TP53 and CTNNB1 gene mutations in the HG component of MASCs as well as detection of copy number aberration of EGFR and CCND1 gene did not harbor any abnormalities. All 3 patients with HG-transformed MASC died of disseminated disease within 2 to 6 years after diagnosis. Recognizing HG-transformed MASC and testing for ETV6 rearrangement may be of potential value in patient treatment, because the presence of the ETV6-NTRK3 translocation may represent a therapeutic target in MASC.

Ricarte-Filho JC, Li S, Garcia-Rendueles ME, et al.
Identification of kinase fusion oncogenes in post-Chernobyl radiation-induced thyroid cancers.
J Clin Invest. 2013; 123(11):4935-44 [PubMed] Free Access to Full Article Related Publications
Exposure to ionizing radiation during childhood markedly increases the risk of developing papillary thyroid cancer. We examined tissues from 26 Ukrainian patients with thyroid cancer who were younger than 10 years of age and living in contaminated areas during the time of the Chernobyl nuclear reactor accident. We identified nonoverlapping somatic driver mutations in all 26 cases through candidate gene assays and next-generation RNA sequencing. We found that 22 tumors harbored fusion oncogenes that arose primarily through intrachromosomal rearrangements. Altogether, 23 of the oncogenic drivers identified in this cohort aberrantly activate MAPK signaling, including the 2 somatic rearrangements resulting in fusion of transcription factor ETS variant 6 (ETV6) with neurotrophic tyrosine kinase receptor, type 3 (NTRK3) and fusion of acylglycerol kinase (AGK) with BRAF. Two other tumors harbored distinct fusions leading to overexpression of the nuclear receptor PPARγ. Fusion oncogenes were less prevalent in tumors from a cohort of children with pediatric thyroid cancers that had not been exposed to radiation but were from the same geographical regions. Radiation-induced thyroid cancers provide a paradigm of tumorigenesis driven by fusion oncogenes that activate MAPK signaling or, less frequently, a PPARγ-driven transcriptional program.

Meissner B, Bartram T, Eckert C, et al.
Frequent and sex-biased deletion of SLX4IP by illegitimate V(D)J-mediated recombination in childhood acute lymphoblastic leukemia.
Hum Mol Genet. 2014; 23(3):590-601 [PubMed] Related Publications
Acute lymphoblastic leukemia (ALL) accounts for ∼25% of pediatric malignancies. Of interest, the incidence of ALL is observed ∼20% higher in males relative to females. The mechanism behind the phenomenon of sex-specific differences is presently not understood. Employing genome-wide genetic aberration screening in 19 ALL samples, one of the most recurrent lesions identified was monoallelic deletion of the 5' region of SLX4IP. We characterized this deletion by conventional molecular genetic techniques and analyzed its interrelationships with biological and clinical characteristics using specimens and data from 993 pediatric patients enrolled into trial AIEOP-BFM ALL 2000. Deletion of SLX4IP was detected in ∼30% of patients. Breakpoints within SLX4IP were defined to recurrent positions and revealed junctions with typical characteristics of illegitimate V(D)J-mediated recombination. In initial and validation analyses, SLX4IP deletions were significantly associated with male gender and ETV6/RUNX1-rearranged ALL (both overall P < 0.0001). For mechanistic validation, a second recurrent deletion affecting TAL1 and caused by the same molecular mechanism was analyzed in 1149 T-cell ALL patients. Validating a differential role by sex of illegitimate V(D)J-mediated recombination at the TAL1 locus, 128 out of 1149 T-cell ALL samples bore a deletion and males were significantly more often affected (P = 0.002). The repeatedly detected association of SLX4IP deletion with male sex and the extension of the sex bias to deletion of the TAL1 locus suggest that differential illegitimate V(D)J-mediated recombination events at specific loci may contribute to the consistent observation of higher incidence rates of childhood ALL in boys compared with girls.

Schwaab J, Schnittger S, Sotlar K, et al.
Comprehensive mutational profiling in advanced systemic mastocytosis.
Blood. 2013; 122(14):2460-6 [PubMed] Related Publications
To explore mechanisms contributing to the clinical heterogeneity of systemic mastocytosis (SM) and to suboptimal responses to diverse therapies, we analyzed 39 KIT D816V mutated patients with indolent SM (n = 10), smoldering SM (n = 2), SM with associated clonal hematologic nonmast cell lineage disorder (SM-AHNMD, n = 5), and aggressive SM (n = 15) or mast cell leukemia (n = 7) with (n = 18) or without (n = 4) AHNMD for additional molecular aberrations. We applied next-generation sequencing to investigate ASXL1, CBL, IDH1/2, JAK2, KRAS, MLL-PTD, NPM1, NRAS, TP53, SRSF2, SF3B1, SETBP1, U2AF1 at mutational hotspot regions, and analyzed complete coding regions of EZH2, ETV6, RUNX1, and TET2. We identified additional molecular aberrations in 24/27 (89%) patients with advanced SM (SM-AHNMD, 5/5; aggressive SM/mast cell leukemia, 19/22) whereas only 3/12 (25%) indolent SM/smoldering SM patients carried one additional mutation each (U2AF1, SETBP1, CBL) (P < .001). Most frequently affected genes were TET2, SRSF2, ASXL1, CBL, and RUNX1. In advanced SM, 21/27 patients (78%) carried ≥3 mutations, and 11/27 patients (41%) exhibited ≥5 mutations. Overall survival was significantly shorter in patients with additional aberrations as compared to those with KIT D816V only (P = .019). We conclude that biology and prognosis in SM are related to the pattern of mutated genes that are acquired during disease evolution.

Hwang MJ, Wu PR, Chen CM, et al.
A rare malignancy of the parotid gland in a 13-year-old Taiwanese boy: case report of a mammary analogue secretory carcinoma of the salivary gland with molecular study.
Med Mol Morphol. 2014; 47(1):57-61 [PubMed] Related Publications
Mammary analogue secretory carcinoma (MASC) is a recently described malignancy of the salivary glands characterized by an ETV6-NTRK3 (EN) fusion gene. Morphologically, MASC is sometimes difficult to distinguish from acinic cell carcinoma. Consequently, identifying the chromosomal translocation is essential for diagnosis. We present a case of parotid gland MASC in a 13-year-old boy. To the best of our knowledge, this is the youngest case reported in the literature. Histologic evaluation showed a tumor composed of microcysts, tubular structures, solid nests, or papillary architecture, with secretions within the lumens of the cysts or tubules. Immunohistochemically, tumor cells showed diffuse positive staining of S-100 protein, cytokeratin 19, and vimentin. ETV6 rearrangement was detected by fluorescence in situ hybridization and EN fusion transcripts were verified by reverse transcription (RT-PCR) assay.

Osako T, Takeuchi K, Horii R, et al.
Secretory carcinoma of the breast and its histopathological mimics: value of markers for differential diagnosis.
Histopathology. 2013; 63(4):509-19 [PubMed] Related Publications
AIMS: Secretory carcinoma (SC) is a rare histological type of breast cancer, and ETV6-NTRK3 gene fusion is highly specific to it. The differential diagnoses of SC include acinic cell carcinoma (ACCA) and cystic hypersecretory carcinoma (CHC), as well as invasive ductal carcinoma (IDC). For patients with these rare but distinctive histological subtypes, SC and its histopathological mimics should be differentiated from each other. However, differential markers have not yet been assessed systematically, and we aimed to identify and evaluate novel and existing markers.
METHODS AND RESULTS: We reviewed 19 cases diagnosed initially as SC using integrated diagnostic techniques, including morphology, immunohistochemistry and molecular pathology, and validated promising markers in 445 breast cancers. We reclassified 19 formerly diagnosed 'SCs' into nine SCs, three ACCAs, three CHCs, three IDCs and one microglandular adenosis. We confirmed that ETV6-NTRK3 gene rearrangement and amylase positivity are good diagnostic markers for SC and ACCA, respectively. Vacuolar staining for adipophilin, positivity for α-lactalbumin and negativity for ETV6 rearrangement are diagnostic markers for CHC.
CONCLUSIONS: In this study, we propose a panel of four markers (ETV6 rearrangement, amylase, α-lactalbumin and adipophilin) for distinguishing SC, ACCA, CHC and IDC. This simple but robust panel will serve pathologists well as a practical guide for reaching an appropriate diagnosis.

Al-Sudairy R, Al-Nasser A, Alsultan A, et al.
Clinical characteristics and treatment outcome of childhood acute lymphoblastic leukemia in Saudi Arabia: a multi-institutional retrospective national collaborative study.
Pediatr Blood Cancer. 2014; 61(1):74-80 [PubMed] Related Publications
BACKGROUND: Treatment of childhood acute lymphoblastic leukemia (ALL) has been available in Saudi Arabia (SA) for over 30 years; however, only limited data have been published from there. This study was conducted to establish processes for collaborative data collection and provide clinical characteristics and outcome of children with ALL in SA.
PROCEDURE: Clinical data for patients diagnosed from 2004 to 2008 were retrospectively collected at eight institutions and entered remotely into a custom-built database. Statistics regarding clinical and genetic characteristics and treatment outcome were calculated.
RESULTS: The 594 evaluable patients had a median age of 4.37 years and 56.4% were boys. Majority of patients had B-precursor ALL while 10.7% had T-ALL. CNS leukemia was present in 5.2% of patients. The distribution of common genetic abnormalities was similar to that reported from western populations, with 24.6% hyperdiploidy, 21% RUNX1-ETV6 positivity, 4.2% BCR-ABL1 positivity, and 2.5% with MLL gene rearrangement. Patients received risk-adapted therapy according to various protocols, although treatment strategies for the majority were similar. Five-year OS, RFS and EFS were 86.9%, 79.1%, and 73.3%, respectively. The OS for patients with pre-B ALL was significantly higher than for T-ALL (88.0% vs. 71.8%; P = 0.019, Log-Rank test). Patients with pre-B ALL categorized as low-risk by NCI/Rome criteria and those with hyperdiploidy had OS of 93.4% and 95.8%, respectively.
CONCLUSIONS: The characteristics of childhood ALL in SA are similar to those observed in developed countries. Future prospective studies utilizing unified national protocols are needed to further improve the outcome of our patients.

Konialis C, Savola S, Karapanou S, et al.
Routine application of a novel MLPA-based first-line screening test uncovers clinically relevant copy number aberrations in haematological malignancies undetectable by conventional cytogenetics.
Hematology. 2014; 19(4):217-24 [PubMed] Related Publications
OBJECTIVE: The presence of numerical and/or structural chromosomal abnormalities is a frequent finding in clonal hematopoietic malignant disease, typically diagnosed through routine karyotyping and/or fluorescent in situ hybridization (FISH) analysis. Recently, the application of array comparative genomic hybridization (aCGH) has uncovered many new cryptic genomic copy number imbalances, most of which are now recognized as clinically useful markers of haematological malignancies. In view of the limitations of both FISH and aCGH techniques, in terms of their routine application as a first line screening test, we designed a new multiple ligation-dependent probe amplification (MLPA) probemix for use in addition to classic karyotype analysis.
METHODS: A novel MLPA probemix was developed to interrogate copy number changes involving chromosomal regions: 2p23-24 (MYCN, ALK), 5q32-34 (MIR145A, EBF1, MIR146A), 6q21-27, 7p12.2 (IKZF1), 7q21-36, 8q24.21 (MYC), 9p24 (JAK2 V617F point mutation), 9p21.3 (CDKN2A/2B), 9p13.2 (PAX5), 10q23 (PTEN), 11q22.3 (ATM), 12p13.2 (ETV6), 13q14 (RB1, MIR15A, DLEU2, DLEU1), 17p13.1 (TP53), and 21q22.1 (RUNX1/AML1) and was applied to DNA extracted from 313 consecutive bone marrow patient samples, referred for routine karyotype analysis.
RESULTS: More than half of the samples originated from newly investigated patients. We discovered clinically relevant genomic aberrations, involving a total of 24 patients (8%) all with a normal karyotype, which would have remained undiagnosed.
DISCUSSION: Our data clearly indicate that routine application of this MLPA screening panel, as an adjunct to karyotype analysis, provides a sensitive, robust, rapid and low-cost approach for uncovering clinically important genomic abnormalities, which would have otherwise remained undetected.

Woo J, Seethala RR, Sirintrapun SJ
Mammary analogue secretory carcinoma of the parotid gland as a secondary malignancy in a childhood survivor of atypical teratoid rhabdoid tumor.
Head Neck Pathol. 2014; 8(2):194-7 [PubMed] Free Access to Full Article Related Publications
We report the first case of mammary analogue secretory carcinoma (MASC) arising as a secondary malignancy in a 14 years old child with a history of atypical teratoid rhabdoid tumor (ATRT). Although MASC and ATRT are both rare malignancies, they do not share the same genetic and molecular profiles. MASC is a salivary malignancy characterized by a t(12;15)(p13;q25) translocation, resulting in an ETV6-NTRK3 fusion product encoding for a tyrosine kinase. ATRT is a highly malignant pediatric tumor characterized by a chromosome 22 mutation in the hSNF5/INI1 gene, encoding for a chromatin remodeling protein. Additionally, although mucoepidermoid carcinoma has been described as a secondary malignancy post-therapy for head and neck tumors, MASC has only been reported as a primary malignancy. Our patient was treated with a complete resection of his left sided ATRT at age 3 followed postoperatively with chemoradiotherapy. At age 14 he underwent a parotidectomy for his 1 year history of a left sided preauricular mass and was subsequently diagnosed with MASC. We not only report a case of two rare malignancies in one patient, but also the first case of MASC arising as a secondary malignancy.

Akbari Moqadam F, Lange-Turenhout EA, Ariës IM, et al.
MiR-125b, miR-100 and miR-99a co-regulate vincristine resistance in childhood acute lymphoblastic leukemia.
Leuk Res. 2013; 37(10):1315-21 [PubMed] Related Publications
MicroRNA-125b (miR-125b), miR-99a and miR-100 are overexpressed in vincristine-resistant acute lymphoblastic leukemia (ALL). Cellular viability of ETV6-RUNX1-positive Reh cells significantly increased in presence of 9 ng/mL vincristine upon co-expression of miR-125b/miR-99a (91 ± 4%), miR-125b/miR-100 (93 ± 5%) or miR-125b/miR-99a/miR-100 (82 ± 17%) compared with miR-125b-transduced cells (38 ± 13%, P<0.05). Co-expression of these miRNAs resulted in downregulation of DNTT, NUCKS1, MALAT1, SNRPE, PNO1, SET, KIF5B, PRPS2, RPS11, RPL38 and RPL23A (fold-change 1.3-1.9, p<0.05). Similarly, 7 out of these genes are lower expressed in vincristine-resistant ALL cells of children (p<0.05). The concerted function of miR-125b in combination with miR-99a and/or miR-100 illustrates the complexity of vincristine-resistant pediatric ALL.

Cario G, Rhein P, Mitlöhner R, et al.
High CD45 surface expression determines relapse risk in children with precursor B-cell and T-cell acute lymphoblastic leukemia treated according to the ALL-BFM 2000 protocol.
Haematologica. 2014; 99(1):103-10 [PubMed] Free Access to Full Article Related Publications
Further improvement of outcome in childhood acute lymphoblastic leukemia could be achieved by identifying additional high-risk patients who may benefit from intensified treatment. We earlier identified PTPRC (CD45) gene expression as a potential new stratification marker and now analyzed the prognostic relevance of CD45 protein expression. CD45 was measured by flow cytometry in 1065 patients treated according to the ALL-BFM-2000 protocol. The 75(th) percentile was used as cut-off to distinguish a CD45-high from a CD45-low group. As mean CD45 expression was significantly higher in T-cell acute lymphoblastic leukemia than in B-cell-precursor acute lymphoblastic leukemia (P<0.0001), the analysis was performed separately in both groups. In B-cell-precursor acute lymphoblastic leukemia we observed a significant association of a high CD45 expression with older age, high initial white blood cell count, ETV6/RUNX1 negativity, absence of high hyperdiploidy (P<0.0001), MLL/AF4 positivity (P=0.002), BCR/ABL1 positivity (P=0.007), prednisone poor response (P=0.002) and minimal residual disease (P<0.0001). In T-cell acute lymphoblastic leukemia we observed a significant association with initial white blood cell count (P=0.0003), prednisone poor response (P=0.01), and minimal residual disease (P=0.02). Compared to CD45-low patients, CD45-high patients had a lower event-free survival rate (B-cell-precursor acute lymphoblastic leukemia: 72 ± 3% versus 86 ± 1%, P<0.0001; T-cell acute lymphoblastic leukemia: 60 ± 8% versus 78 ± 4%, P=0.02), which was mainly attributable to a higher cumulative relapse incidence (B-cell-precursor acute lymphoblastic leukemia: 22 ± 3% versus 11 ± 1%, P<0.0001; T-cell acute lymphoblastic leukemia: 31 ± 8% versus 11 ± 3%, P=0.003) and kept its significance in multivariate analysis considering sex, age, initial white blood cell count, and minimal residual disease in B-cell-precursor- and T-cell acute lymphoblastic leukemia, and additionally presence of ETV6/RUNX1, MLL/AF4 and BCR/ABL1 rearrangements in B-cell-precursor acute lymphoblastic leukemia (P=0.002 and P=0.025, respectively). Consideration of CD45 expression may serve as an additional stratification tool in BFM-based protocols. (ClinicalTrials.gov identifier: NCT00430118).

Carranza C, Granados L, Morales O, et al.
Frequency of the ETV6-RUNX1, BCR-ABL1, TCF3-PBX1, and MLL-AFF1 fusion genes in Guatemalan pediatric acute lymphoblastic leukemia patients and their ethnic associations.
Cancer Genet. 2013; 206(6):227-32 [PubMed] Related Publications
Fusion genes involved in acute lymphoblastic leukemia (ALL) occur mostly due to genetic and environmental factors, and only a limited number of studies have reported any ethnic influence. This study assesses whether an ethnic influence has an effect on the frequency of any of the four fusion genes: BCR-ABL1, ETV6-RUNX1, TCF3-PBX1, and MLL-AFF1 found in ALL. To study this ethnic influence, mononuclear cells were obtained from bone marrow samples from 143 patients with ALL. We performed RNA extraction and reverse transcription, then assessed the quality of the cDNA by amplifying the ABL1 control gene, and finally evaluated the presence of the four transcripts by multiplex polymerase chain reaction. We found 10 patients who had the BCR-ABL1 fusion gene (7%); 3 patients (2%) were TCF3-PBX1 positive; and 6 patients (4.5%) were ETV6-RUNX1 positive. The incidence of this last fusion gene is quite low when compared to the values reported in most countries. The low incidence of the ETV6-RUNX1 fusion gene found in Guatemala matches the incidence rates that have been reported in Spain and Indian Romani. Since it is known that an ethnic resemblance exists among these three populations, as shown by ancestral marker studies, the ALL data suggests an ethnic influence on the occurrence and frequency of this particular fusion gene.

Stenman G
Fusion oncogenes in salivary gland tumors: molecular and clinical consequences.
Head Neck Pathol. 2013; 7 Suppl 1:S12-9 [PubMed] Free Access to Full Article Related Publications
Salivary gland tumors constitute a heterogeneous group of uncommon diseases that pose significant diagnostic and therapeutic challenges. However, the recent discovery of a translocation-generated gene fusion network in salivary gland carcinomas as well in benign salivary gland tumors opens up new avenues for improved diagnosis, prognostication, and development of specific targeted therapies. The gene fusions encode novel fusion oncoproteins or ectopically expressed normal or truncated oncoproteins. The major targets of the translocations are transcriptional coactivators, tyrosine kinase receptors, and transcription factors involved in growth factor signaling and cell cycle regulation. Notably, several of these targets or pathways activated by these targets are druggable. Examples of clinically significant gene fusions in salivary gland cancers are the MYB-NFIB fusion specific for adenoid cystic carcinoma, the CRTC1-MAML2 fusion typical of low/intermediate-grade mucoepidermoid carcinoma, and the recently identified ETV6-NTRK3 fusion in mammary analogue secretory carcinoma. Similarly, gene fusions involving the PLAG1 and HMGA2 oncogenes are specific for benign pleomorphic adenomas. Continued studies of the molecular consequences of these fusion oncoproteins and their down-stream targets will ultimately lead to the identification of novel driver genes in salivary gland neoplasms and will also form the basis for the development of new therapeutic strategies for salivary gland cancers and, perhaps, other neoplasms.

Further References

Kobayashi H, Satake N, Kaneko Y
Detection of the Der (21)t(12;21) chromosome forming the TEL-AML1 fusion gene in childhood acute lymphoblastic leukemia.
Leuk Lymphoma. 1997; 28(1-2):43-50 [PubMed] Related Publications
The t(12;21) (p13;q22) is observed in approximately 20-25% of childhood B-lineage acute lymphoblastic leukemia (ALL) cases in both Asian and Caucasian populations. This translocation results in the fusion of TEL, a recently described ETS-like gene on 12p13, and AML1, which was shown to be involved in the formation of fusion genes with ETO and EVI1 in myeloid leukemias. Fluorescence in situ hybridization (FISH) and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis are useful in detecting this translocation which is not readily identified with routine cytogenetic techniques. The t(12;21) is associated with a distinct subgroup of patients characterized by an age between 1 and 10 years, an early B immunophenotype, and a good prognosis. A high incidence of the deletion of non-translocated TEL is another characteristic of leukemic cells with this translocation. TEL-AML1 hybrid protein thought to be critical in leukemogenesis possesses the HLH domain of TEL fused to almost the entire AML1 protein, although the detailed mechanisms of leukemogenesis remain obscure. RT-PCR combined with FISH analysis of posttreatment samples appears to be useful in detecting early relapse or minimal residual disease and thus, is expected to optimize the treatment strategy for patients with t(12;21).

Aguiar RC, Sohal J, van Rhee F, et al.
TEL-AML1 fusion in acute lymphoblastic leukaemia of adults. M.R.C. Adult Leukaemia Working Party.
Br J Haematol. 1996; 95(4):673-7 [PubMed] Related Publications
A number of fusion genes have been identified by study of acquired chromosomal translocations. Their detailed characterization has provided insights into mechanisms of leukaemogenesis and has enabled the development of molecular methods to assist in the diagnosis and monitoring of residual disease after treatment. The TEL-AML1 fusion gene is associated with a cryptic t(12:21)(p12:q22) translocation, and is the commonest known genetic abnormality in childhood B-cell precursor acute lymphoblastic leukaemia (ALL), occurring in about 25% of cases. We have used RT-PCR, followed by Southern blotting and direct sequencing, to establish the incidence of TEL-AML1 rearrangement in 131 adults with acute leukaemia (101 with ALL and 30 with chronic myeloid leukaemia in blastic crisis). Three patients were positive for TEL-AML1 transcripts. All three had common-ALL. All other patients were negative for TEL-AML1. We conclude that the TEL-AML1 fusion gene is found in adult ALL, though less commonly than in children.

Kwong YL, Wong KF
Low frequency of TEL/AML1 in adult acute lymphoblastic leukemia.
Cancer Genet Cytogenet. 1997; 98(2):137-8 [PubMed] Related Publications
Translocation (12;21)(p13;q22) is a recently characterized aberration in acute lymphoblastic leukemia, and results in the fusion of the TEL and the AML1 genes. It is the most common translocation in pediatric acute lymphoblastic leukemia (ALL), occurring in about one third of the cases. To determine the frequency of TEL/AML1 in adult ALL, we studied 4 cases of T lineage ALL and 26 cases of B lineage ALL. Only one positive case was identified, giving a very low frequency of 3.3%. In this patient, TEL/AML1 was still detectable in complete hematologic remission. The apparent age predilection of t(12;21) warrants further investigations.

Zhou MH, Gao L, Jing Y, et al.
Detection of ETV6 gene rearrangements in adult acute lymphoblastic leukemia.
Ann Hematol. 2012; 91(8):1235-43 [PubMed] Related Publications
ETV6 is an important hematopoietic regulatory factor and ETV6 gene rearrangement is involved in a wide variety of hematological malignancies. In this study, we sought to investigate the incidence of ETV6-associated fusion genes in B- and T-lineage acute lymphoblastic leukemia (ALL) by multiplex-nested reverse transcription-polymerase chain reaction (RT-PCR) in 176 adult ALL patients. Total RNA was extracted from bone marrow samples of ALL patients including 136 B- and 40 T-lineage ALL, and ETV6 fusion genes were detected by multiplex-nested RT-PCR. Changes of ETV6 fusion gene mRNA transcript levels were examined by real-time RT-PCR. We detected a total of 15 ETV6 gene rearrangements with a positive rate of 8.5%, involving seven ETV6-associated fusion genes in 13 B-ALL (13/136, 9.6%) and 2 T-ALL patients (2/40, 5.0%). ETV6-RUNX1 were observed in six cases (3.4%), ETV6-JAK2 in three cases (1.7%), ETV6-ABL1 in two cases (1.1%), and ETV6-ABL2, ETV6-NCOA2, ETV6-SYK, and PAX5-ETV6 each in one case (0.6%). ETV6-JAK2 was found in both B-ALL and T-ALL patients. Furthermore, real-time quantitative RT-PCR assays showed that the ETV6-RUNX1 mRNA transcript levels decreased during conventional chemotherapy or hematopoietic stem cell transplantation. This study shows that multiplex-nested RT-PCR is an effective and accurate tool to identify ETV6 rearrangements in adult ALL, which provides some clues into the diagnosis and prognosis of ALL but also molecular markers for the detection of minimal residual disease in adult ALL.

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