Research IndicatorsGraph generated 16 March 2017 using data from PubMed using criteria.
Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic. Tag cloud generated 16 March, 2017 using data from PubMed, MeSH and CancerIndex
Specific Cancers (1)
Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.
Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).
OMIM, Johns Hopkin University
Referenced article focusing on the relationship between phenotype and genotype.
International Cancer Genome Consortium.
Summary of gene and mutations by cancer type from ICGC
Cancer Genome Anatomy Project, NCI
COSMIC, Sanger Institute
Somatic mutation information and related details
TICdb, Universidad de Navarra
Search the database of Translocation breakpoints In Cancer for "EBF1"
GEO Profiles, NCBI
Search the gene expression profiles from curated DataSets in the Gene Expression Omnibus (GEO) repository.
Latest Publications: EBF1 (cancer-related)
Appiah-Kubi K, Lan T, Wang Y, et al.Platelet-derived growth factor receptors (PDGFRs) fusion genes involvement in hematological malignancies.
Crit Rev Oncol Hematol. 2017; 109:20-34 [PubMed
] Related Publications
PURPOSE: To investigate oncogenic platelet-derived growth factor receptor(PDGFR) fusion genes involvement in hematological malignancies, the advances in the PDGFR fusion genes diagnosis and development of PDGFR fusions inhibitors.
METHODS: Literature search was done using terms "PDGFR and Fusion" or "PDGFR and Myeloid neoplasm" or 'PDGFR and Lymphoid neoplasm' or "PDGFR Fusion Diagnosis" or "PDGFR Fusion Targets" in databases including PubMed, ASCO.org, and Medscape.
RESULTS: Out of the 36 fusions detected, ETV6(TEL)-PDGFRB and FIP1L1-PDGFRA fusions were frequently detected, 33 are as a result of chromosomal translocation, FIP1L1-PDGFRA and EBF1-PDGFRB are the result of chromosomal deletion and CDK5RAP2- PDGFRΑ is the result of chromosomal insertion. Seven of the 34 rare fusions have detectable reciprocals.
CONCLUSION: RNA aptamers are promising therapeutic target of PDGFRs and diagnostic tools of PDGFRs fusion genes. Also, PDGFRs have variable prospective therapeutic strategies including small molecules, RNA aptamers, and interference therapeutics as well as development of adaptor protein Lnk mimetic drugs.
UNLABELLED: Latent membrane protein 1 (LMP1) is a major oncogene essential for primary B cell transformation by Epstein-Barr virus (EBV). Previous studies suggested that some transcription factors, such as PU.1, RBP-Jκ, NF-κB, and STAT, are involved in this expression, but the underlying mechanism is unclear. Here, we identified binding sites for PAX5, AP-2, and EBF in the proximal LMP1 promoter (ED-L1p). We first confirmed the significance of PU.1 and POU domain transcription factor binding for activation of the promoter in latency III. We then focused on the transcription factors AP-2 and early B cell factor (EBF). Interestingly, among the three AP-2-binding sites in the LMP1 promoter, two motifs were also bound by EBF. Overexpression, knockdown, and mutagenesis in the context of the viral genome indicated that AP-2 plays an important role in LMP1 expression in latency II in epithelial cells. In latency III B cells, on the other hand, the B cell-specific transcription factor EBF binds to the ED-L1p and activates LMP1 transcription from the promoter.
IMPORTANCE: Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) is crucial for B cell transformation and oncogenesis of other EBV-related malignancies, such as nasopharyngeal carcinoma and T/NK lymphoma. Its expression is largely dependent on the cell type or condition, and some transcription factors have been implicated in its regulation. However, these previous reports evaluated the significance of specific factors mostly by reporter assay. In this study, we prepared point-mutated EBV at the binding sites of such transcription factors and confirmed the importance of AP-2, EBF, PU.1, and POU domain factors. Our results will provide insight into the transcriptional regulation of the major oncogene LMP1.
The development of the B-lymphoid cell lineage is tightly controlled by the concerted action of a network of transcriptional and epigenetic regulators. EBF1, a central component of this network, is essential for B-lymphoid specification and commitment as well as for the maintenance of the B-cell identity. Genetic alterations causing loss of function of these B-lymphopoiesis regulators have been implicated in the pathogenesis of B-lymphoid malignancies, with particular regard to B-cell acute lymphoblastic leukaemias (B-ALLs), where their presence is frequently detected. The activity of the B-cell regulatory network may also be disrupted by the aberrant expression of inhibitory molecules. In particular, two multi-zinc finger transcription cofactors named ZNF423 and ZNF521 have been characterised as potent inhibitors of EBF1 and are emerging as potentially relevant contributors to the development of B-cell leukaemias. Here we will briefly review the current knowledge of these factors and discuss the importance of their functional cross talk with EBF1 in the development of B-cell malignancies.
Charting differences between tumors and normal tissue is a mainstay of cancer research. However, clonal tumor expansion from complex normal tissue architectures potentially obscures cancer-specific events, including divergent epigenetic patterns. Using whole-genome bisulfite sequencing of normal B cell subsets, we observed broad epigenetic programming of selective transcription factor binding sites coincident with the degree of B cell maturation. By comparing normal B cells to malignant B cells from 268 patients with chronic lymphocytic leukemia (CLL), we showed that tumors derive largely from a continuum of maturation states reflected in normal developmental stages. Epigenetic maturation in CLL was associated with an indolent gene expression pattern and increasingly favorable clinical outcomes. We further uncovered that most previously reported tumor-specific methylation events are normally present in non-malignant B cells. Instead, we identified a potential pathogenic role for transcription factor dysregulation in CLL, where excess programming by EGR and NFAT with reduced EBF and AP-1 programming imbalances the normal B cell epigenetic program.
Lu F, Chen HS, Kossenkov AV, et al.EBNA2 Drives Formation of New Chromosome Binding Sites and Target Genes for B-Cell Master Regulatory Transcription Factors RBP-jκ and EBF1.
PLoS Pathog. 2016; 12(1):e1005339 [PubMed
] Free Access to Full Article Related Publications
Epstein-Barr Virus (EBV) transforms resting B-lymphocytes into proliferating lymphoblasts to establish latent infections that can give rise to malignancies. We show here that EBV-encoded transcriptional regulator EBNA2 drives the cooperative and combinatorial genome-wide binding of two master regulators of B-cell fate, namely EBF1 and RBP-jκ. Previous studies suggest that these B-cell factors are statically bound to target gene promoters. In contrast, we found that EBNA2 induces the formation of new binding for both RBP-jκ and EBF1, many of which are in close physical proximity in the cellular and viral genome. These newly induced binding sites co-occupied by EBNA2-EBF1-RBP-jκ correlate strongly with transcriptional activation of linked genes that are important for B-lymphoblast function. Conditional expression or repression of EBNA2 leads to a rapid alteration in RBP-jκ and EBF1 binding. Biochemical and shRNA depletion studies provide evidence for cooperative assembly at co-occupied sites. These findings reveal that EBNA2 facilitate combinatorial interactions to induce new patterns of transcription factor occupancy and gene programming necessary to drive B-lymphoblast growth and survival.
Ribera J, Morgades M, Zamora L, et al.Prognostic significance of copy number alterations in adolescent and adult patients with precursor B acute lymphoblastic leukemia enrolled in PETHEMA protocols.
Cancer. 2015; 121(21):3809-17 [PubMed
] Related Publications
BACKGROUND: Some copy number alterations (CNAs) have independent prognostic significance for adults with acute lymphoblastic leukemia (ALL).
METHODS: This study analyzed via multiplex ligation-dependent probe amplification the frequency and prognostic impact of CNAs of 12 genetic regions in 142 adolescents and adults with de novo precursor B-cell ALL.
RESULTS: The cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) deletion (59 of 142 or 42%) was the most frequent CNA, and it was followed by Ikaros family zinc finger 1 (IKZF1) losses (49 of 142 or 35%). IKZF1 deletions were more prevalent in Philadelphia chromosome (Ph)-positive ALL and were associated with advanced age and high white blood cell (WBC) counts. The multivariate analysis showed that advanced age and early B-cell factor 1 (EBF1) deletions were associated with chemotherapy resistance in both the whole series (hazard ratios, 0.949 and 0.135, respectively) and the Ph-negative subgroup (hazard ratios, 0.946 and 0.118, respectively). High WBC counts and focal IKZF1 deletions correlated with disease recurrence (hazard ratios, 1.005 and 1.869, respectively), whereas advanced age and CDKN2A/B losses influenced overall survival in both the whole series (hazard ratios, 1.038 and 2.545, respectively) and the Ph-negative subgroup (hazard ratios, 1.044 and 2.105, respectively).
CONCLUSIONS: Deletions of EBF1, IKZF1, and CDKN2A/B have an independent adverse prognosis for adolescents and adults with B-precursor ALL, and this suggests that these CNAs should be included in the initial risk assessment of ALL.
B-lymphocyte development in the bone marrow is controlled by the coordinated action of transcription factors creating regulatory networks ensuring activation of the B-lymphoid program and silencing of alternative cell fates. This process is tightly connected to malignant transformation because B-lineage acute lymphoblastic leukemia cells display a pronounced block in differentiation resulting in the expansion of immature progenitor cells. Over the last few years, high-resolution analysis of genetic changes in leukemia has revealed that several key regulators of normal B-cell development, including IKZF1, TCF3, EBF1, and PAX5, are genetically altered in a large portion of the human B-lineage acute leukemias. This opens the possibility of directly linking the disrupted development as well as aberrant gene expression patterns in leukemic cells to molecular functions of defined transcription factors in normal cell differentiation. This review article focuses on the roles of transcription factors in early B-cell development and their involvement in the formation of human leukemia.
Recent investigation has identified association of IL-12p40 blood levels with melanoma recurrence and patient survival. No studies have investigated associations of single-nucleotide polymorphisms (SNPs) with melanoma patient IL-12p40 blood levels or their potential contributions to melanoma susceptibility or patient outcome. In the current study, 818,237 SNPs were available for 1,804 melanoma cases and 1,026 controls. IL-12p40 blood levels were assessed among 573 cases (discovery), 249 cases (case validation), and 299 controls (control validation). SNPs were evaluated for association with log[IL-12p40] levels in the discovery data set and replicated in two validation data sets, and significant SNPs were assessed for association with melanoma susceptibility and patient outcomes. The most significant SNP associated with log[IL-12p40] was in the IL-12B gene region (rs6897260, combined P=9.26 × 10(-38)); this single variant explained 13.1% of variability in log[IL-12p40]. The most significant SNP in EBF1 was rs6895454 (combined P=2.24 × 10(-9)). A marker in IL12B was associated with melanoma susceptibility (rs3213119, multivariate P=0.0499; OR=1.50, 95% CI 1.00-2.24), whereas a marker in EBF1 was associated with melanoma-specific survival in advanced-stage patients (rs10515789, multivariate P=0.02; HR=1.93, 95% CI 1.11-3.35). Both EBF1 and IL12B strongly regulate IL-12p40 blood levels, and IL-12p40 polymorphisms may contribute to melanoma susceptibility and influence patient outcome.
Ogawara Y, Katsumoto T, Aikawa Y, et al.IDH2 and NPM1 Mutations Cooperate to Activate Hoxa9/Meis1 and Hypoxia Pathways in Acute Myeloid Leukemia.
Cancer Res. 2015; 75(10):2005-16 [PubMed
] Related Publications
IDH1 and IDH2 mutations occur frequently in acute myeloid leukemia (AML) and other cancers. The mutant isocitrate dehydrogenase (IDH) enzymes convert α-ketoglutarate (α-KG) to the oncometabolite 2-hydroxyglutarate (2-HG), which dysregulates a set of α-KG-dependent dioxygenases. To determine whether mutant IDH enzymes are valid targets for cancer therapy, we created a mouse model of AML in which mice were transplanted with nucleophosmin1 (NPM)(+/-) hematopoietic stem/progenitor cells cotransduced with four mutant genes (NPMc, IDH2/R140Q, DNMT3A/R882H, and FLT3/ITD), which often occur simultaneously in human AML patients. Conditional deletion of IDH2/R140Q blocked 2-HG production and maintenance of leukemia stem cells, resulting in survival of the AML mice. IDH2/R140Q was necessary for the engraftment or survival of NPMc(+) cells in vivo. Gene expression analysis indicated that NPMc increased expression of Hoxa9. IDH2/R140Q also increased the level of Meis1 and activated the hypoxia pathway in AML cells. IDH2/R140Q decreased the 5hmC modification and expression of some differentiation-inducing genes (Ebf1 and Spib). Taken together, our results indicated that IDH2 mutation is critical for the development and maintenance of AML stem-like cells, and they provided a preclinical justification for targeting mutant IDH enzymes as a strategy for anticancer therapy.
Kęsy J, Januszkiewicz-Lewandowska DGenes and childhood leukemia.
Postepy Hig Med Dosw (Online). 2015; 69:302-8 [PubMed
] Related Publications
Leukemia is a heterogeneous hematologic malignancy originating from a multipotent hematopoietic stem cell. It ranks among the commonest cancers in childhood and is characterized by excessive proliferation and differentiation block. The process of leukemogenesis is governed by genetic changes at both the cytogenetic and molecular level. According to numerous analyses, a large spectrum of mutations and rearrangements underlying the disease affect essential cellular transduction pathways, genes ensuring proper course of hematopoiesis, oncogenes, tumor suppressors and apoptosis regulators. Common lesions include translocations to T cell receptor (TCR) loci in T-lineage acute lymphoblastic leukemia (T-ALL), mutations of transcription factors regulating B-lineage development and cell maturation in B-lineage acute lymphoblastic leukemia (B-ALL) (PAX5, TCF3, EBF1, etc.), aberrational disruption of genes coding for transcription factors and coactivators in acute myeloid leukemia (AML) (e.g. CBF) or BCR-ABL1 fusion and activation of multiple kinases in chronic myeloid leukemia (CML). These alterations severely impair cell function. Broadening knowledge of the genetic background gives an insight into the pathobiology of a disease and allows for a better understanding of it. An appropriate investigation of genomic events yields diagnostic, prognostic and therapeutic implications. Broadening knowledge of the pathogenesis of leukemia seems to be a promising contribution to precise stratification of patients, reducing the toxicity and adverse effects caused by medical intervention, treatment personalization and introduction of targeted therapy accessible to a wide range of patients.
In contrast to acute lymphoblastic leukemia in children, adult cases of this disease are associated with a very poor prognosis. In order to ascertain whether the frequencies and patterns of submicroscopic changes, identifiable with single nucleotide polymorphism array analysis, differ between childhood and adult acute lymphoblastic leukemia, we performed single nucleotide polymorphism array analyses of 126 adult cases, the largest series to date, including 18 paired diagnostic and relapse samples. Apart from identifying characteristic microdeletions of the CDKN2A, EBF1, ETV6, IKZF1, PAX5 and RB1 genes, the present study uncovered novel, focal deletions of the BCAT1, BTLA, NR3C1, PIK3AP1 and SERP2 genes in 2-6% of the adult cases. IKZF1 deletions were associated with B-cell precursor acute lymphoblastic leukemia (P=0.036), BCR-ABL1-positive acute lymphoblastic leukemia (P<0.001), and higher white blood cell counts (P=0.005). In addition, recurrent deletions of RASSF3 and TOX were seen in relapse samples. Comparing paired diagnostic/relapse samples revealed identical changes at diagnosis and relapse in 27%, clonal evolution in 22%, and relapses evolving from ancestral clones in 50%, akin to what has previously been reported in pediatric acute lymphoblastic leukemia and indicating that the mechanisms of relapse may be similar in adult and childhood cases. These findings provide novel insights into the leukemogenesis of adult acute lymphoblastic leukemia, showing similarities to childhood disease in the pattern of deletions and the clonal relationship between diagnostic and relapse samples, but with the adult cases harboring additional aberrations that have not been described in pediatric acute lymphoblastic leukemia.
Hanada I, Terui K, Ikeda F, et al.Gene alterations involving the CRLF2-JAK pathway and recurrent gene deletions in Down syndrome-associated acute lymphoblastic leukemia in Japan.
Genes Chromosomes Cancer. 2014; 53(11):902-10 [PubMed
] Related Publications
In Western countries, gene alterations involving the CRLF2-JAK signaling pathway are identified in approximately 50-60% of patients with Down syndrome-associated acute lymphoblastic leukemia (DS-ALL), and this pathway is considered a potential therapeutic target. The frequency of BTG1 deletions in DS-ALL is controversial. IKZF1 deletions, found in 20-30% of DS-ALL patients, are associated with a poor outcome and EBF1 deletions are very rare (∼2%). We analyzed 38 patients to determine the frequencies and clinical implications of CRLF2-JAK pathway genetic alterations and recurrent gene deletions in Japanese DS-ALL patients. We confirmed a high incidence of P2RY8-CRLF2 (29%) and JAK2 mutations (16%), though the frequency of P2RY8-CRLF2 was slightly lower than that in Western countries (∼50%). BTG1 deletions were common in our cohort (25%). IKZF1 deletions were detected in 25% of patients and associated with shorter overall survival (OS). EBF1 deletions were found at an unexpectedly high frequency (16%), and at a significantly higher level in P2RY8-CRLF2-positive patients than in P2RY8-CRLF2-negative patients (44% vs. 4%, P=0.015). Deletions of CDKN2A/B and PAX5 were common in P2RY8-CRLF2-negative patients (48 and 39%, respectively) but not in P2RY8-CRLF2-positive patients (11% each). Associations between these genetic alterations and clinical characteristics were not observed except for inferior OS in patients with IKZF1 deletions. These results suggest that differences exist between the genetic profiles of DS-ALL patients in Japan and in Western countries, and that P2RY8-CRLF2 and EBF1 deletions may cooperate in leukemogenesis in a subset of Japanese DS-ALL patients.
Little is known about the genomic basis of primary central nervous system lymphoma (PCNSL) tumorigenesis. To investigate the mutational profile of PCNSL, we analyzed nine paired tumor and germline DNA samples from PCNSL patients by high throughput exome sequencing. Eight genes of interest have been further investigated by focused resequencing in 28 additional PCNSL tumors to better estimate their incidence. Our study identified recurrent somatic mutations in 37 genes, some involved in key signaling pathways such as NFKB, B cell differentiation and cell cycle control. Focused resequencing in the larger cohort revealed high mutation rates for genes already described as mutated in PCNSL such as MYD88 (38%), CD79B (30%), PIM1 (22%) and TBL1XR1 (19%) and for genes not previously reported to be involved in PCNSL tumorigenesis such as ETV6 (16%), IRF4 (14%), IRF2BP2 (11%) and EBF1 (11%). Of note, only 3 somatically acquired SNVs were annotated in the COSMIC database. Our results demonstrate a high genetic heterogeneity of PCNSL and mutational pattern similarities with extracerebral diffuse large B cell lymphomas, particularly of the activated B-cell (ABC) subtype, suggesting shared underlying biological mechanisms. The present study provides new insights into the mutational profile of PCNSL and potential targets for therapeutic strategies.
Pang SH, Carotta S, Nutt SLTranscriptional control of pre-B cell development and leukemia prevention.
Curr Top Microbiol Immunol. 2014; 381:189-213 [PubMed
] Related Publications
The differentiation of early B cell progenitors is controlled by multiple transcriptional regulators and growth-factor receptors. The triad of DNA-binding proteins, E2A, EBF1, and PAX5 is critical for both the early specification and commitment of B cell progenitors, while a larger number of secondary determinants, such as members of the Ikaros, ETS, Runx, and IRF families have more direct roles in promoting stage-specific pre-B gene-expression program. Importantly, it is now apparent that mutations in many of these transcription factors are associated with the progression to acute lymphoblastic leukemia. In this review, we focus on recent studies that have shed light on the transcriptional hierarchy that controls efficient B cell commitment and differentiation as well as focus on the oncogenic consequences of the loss of many of the same factors.
Follicular lymphoma is an incurable malignancy, with transformation to an aggressive subtype representing a critical event during disease progression. Here we performed whole-genome or whole-exome sequencing on 10 follicular lymphoma-transformed follicular lymphoma pairs followed by deep sequencing of 28 genes in an extension cohort, and we report the key events and evolutionary processes governing tumor initiation and transformation. Tumor evolution occurred through either a 'rich' or 'sparse' ancestral common progenitor clone (CPC). We identified recurrent mutations in linker histone, JAK-STAT signaling, NF-κB signaling and B cell developmental genes. Longitudinal analyses identified early driver mutations in chromatin regulator genes (CREBBP, EZH2 and KMT2D (MLL2)), whereas mutations in EBF1 and regulators of NF-κB signaling (MYD88 and TNFAIP3) were gained at transformation. Collectively, this study provides new insights into the genetic basis of follicular lymphoma and the clonal dynamics of transformation and suggests that personalizing therapies to target key genetic alterations in the CPC represents an attractive therapeutic strategy.
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.
Okuyama K, Ikawa T, Gentner B, et al.MicroRNA-126-mediated control of cell fate in B-cell myeloid progenitors as a potential alternative to transcriptional factors.
Proc Natl Acad Sci U S A. 2013; 110(33):13410-5 [PubMed
] Free Access to Full Article Related Publications
Lineage specification is thought to be largely regulated at the level of transcription, where lineage-specific transcription factors drive specific cell fates. MicroRNAs (miR), vital to many cell functions, act posttranscriptionally to decrease the expression of target mRNAs. MLL-AF4 acute lymphocytic leukemia exhibits both myeloid and B-cell surface markers, suggesting that the transformed cells are B-cell myeloid progenitor cells. Through gain- and loss-of-function experiments, we demonstrated that microRNA 126 (miR-126) drives B-cell myeloid biphenotypic leukemia differentiation toward B cells without changing expression of E2A immunoglobulin enhancer-binding factor E12/E47 (E2A), early B-cell factor 1 (EBF1), or paired box protein 5, which are critical transcription factors in B-lymphopoiesis. Similar induction of B-cell differentiation by miR-126 was observed in normal hematopoietic cells in vitro and in vivo in uncommitted murine c-Kit(+)Sca1(+)Lineage(-) cells, with insulin regulatory subunit-1 acting as a target of miR-126. Importantly, in EBF1-deficient hematopoietic progenitor cells, which fail to differentiate into B cells, miR-126 significantly up-regulated B220, and induced the expression of B-cell genes, including recombination activating genes-1/2 and CD79a/b. These data suggest that miR-126 can at least partly rescue B-cell development independently of EBF1. These experiments show that miR-126 regulates myeloid vs. B-cell fate through an alternative machinery, establishing the critical role of miRNAs in the lineage specification of multipotent mammalian cells.
Nasopharyngeal carcinoma (NPC) is a distinct type of head and neck cancer which is prevalent in southern China, south-east Asia and northern Africa. The development and stepwise progression of NPC involves accumulation of multiple gross genetic changes during the clonal expansion of Epstein-Barr virus (EBV)-infected nasopharyngeal epithelial cell population. Here, using paired-end whole-transcriptome sequencing, we discovered a number of chimeric fusion transcripts in a panel of EBV-positive tumour lines. Among these transcripts, a novel fusion of ubiquitin protein ligase E3 component n-recognin 5 (UBR5) on 8q22.3 and zinc finger protein 423 (ZNF423) on 16q12.1, identified from the NPC cell line C666-1, was recurrently detected in 12/144 (8.3%) of primary tumours. The fusion gene contains exon 1 of UBR5 and exons 7-9 of ZNF423 and produces a 94 amino acid chimeric protein including the original C-terminal EBF binding domain (ZF29-30) of ZNF423. Notably, the growth of NPC cells with UBR5-ZNF423 rearrangement is dependent on expression of this fusion protein. Knock-down of UBR5-ZNF423 by fusion-specific siRNA significantly inhibited the cell proliferation and colony-forming ability of C666-1 cells. The transforming ability of UBR5-ZNF423 fusion was also confirmed in NIH3T3 fibroblasts. Constitutive expression of UBR5-ZNF423 in NIH3T3 fibroblasts significantly enhanced its anchorage-independent growth in soft agar and induced tumour formation in a nude mouse model. These findings suggest that expression of UBR5-ZNF423 protein might contribute to the transformation of a subset of NPCs, possibly by altering the activity of EBFs (early B cell factors). Identification of the oncogenic UBR5-ZNF423 provides new potential opportunities for therapeutic intervention in NPC.
Isocitrate dehydrogenase (IDH) genes 1 and 2 are frequently mutated in acute myeloid leukaemia (AML), low-grade glioma, cholangiocarcinoma (CC) and chondrosarcoma (CS). For AML, low-grade glioma and CC, mutant IDH status is associated with a DNA hypermethylation phenotype, implicating altered epigenome dynamics in the aetiology of these cancers. Here we show that the IDH variants in CS are also associated with a hypermethylation phenotype and display increased production of the oncometabolite 2-hydroxyglutarate, supporting the role of mutant IDH-produced 2-hydroxyglutarate as an inhibitor of TET-mediated DNA demethylation. Meta-analysis of the acute myeloid leukaemia, low-grade glioma, cholangiocarcinoma and CS methylation data identifies cancer-specific effectors within the retinoic acid receptor activation pathway among the hypermethylated targets. By analysing sequence motifs surrounding hypermethylated sites across the four cancer types, and using chromatin immunoprecipitation and western blotting, we identify the transcription factor EBF1 (early B-cell factor 1) as an interaction partner for TET2, suggesting a sequence-specific mechanism for regulating DNA methylation.
Olsson L, Castor A, Behrendtz M, et al.Deletions of IKZF1 and SPRED1 are associated with poor prognosis in a population-based series of pediatric B-cell precursor acute lymphoblastic leukemia diagnosed between 1992 and 2011.
Leukemia. 2014; 28(2):302-10 [PubMed
] Related Publications
Despite the favorable prognosis of childhood acute lymphoblastic leukemia (ALL), a substantial subset of patients relapses. As this occurs not only in the high risk but also in the standard/intermediate groups, the presently used risk stratification is suboptimal. The underlying mechanisms for treatment failure include the presence of genetic changes causing insensitivity to the therapy administered. To identify relapse-associated aberrations, we performed single-nucleotide polymorphism array analyses of 307 uniformly treated, consecutive pediatric ALL cases accrued during 1992-2011. Recurrent aberrations of 14 genes in patients who subsequently relapsed or had induction failure were detected. Of these, deletions/uniparental isodisomies of ADD3, ATP10A, EBF1, IKZF1, PAN3, RAG1, SPRED1 and TBL1XR1 were significantly more common in B-cell precursor ALL patients who relapsed compared with those remaining in complete remission. In univariate analyses, age (≥10 years), white blood cell counts (>100 × 10(9)/l), t(9;22)(q34;q11), MLL rearrangements, near-haploidy and deletions of ATP10A, IKZF1, SPRED1 and the pseudoautosomal 1 regions on Xp/Yp were significantly associated with decreased 10-year event-free survival, with IKZF1 abnormalities being an independent risk factor in multivariate analysis irrespective of the risk group. Older age and deletions of IKZF1 and SPRED1 were also associated with poor overall survival. Thus, analyses of these genes provide clinically important information.
The characterization of immunoglobulin heavy chain (IGH) translocations provides information on the diagnosis and guides therapeutic decisions in mature B-cell malignancies while enhancing our understanding of normal and malignant B-cell biology. However, existing methodologies for the detection of IGH translocations are labor intensive, often require viable cells, and are biased toward known IGH fusions. To overcome these limitations, we developed a capture sequencing strategy for the identification of IGH rearrangements at nucleotide level resolution and tested its capabilities as a diagnostic and discovery tool in 78 primary diffuse large B-cell lymphomas (DLBCLs). We readily identified IGH-BCL2, IGH-BCL6, IGH-MYC, and IGH-CCND1 fusions and discovered IRF8, EBF1, and TNFSF13 (APRIL) as novel IGH partners in these tumors. IRF8 and TNFSF13 expression was significantly higher in lymphomas with IGH rearrangements targeting these loci. Modeling the deregulation of IRF8 and EBF1 in vitro defined a lymphomagenic profile characterized by up-regulation of AID and/or BCL6, down-regulation of PRMD1, and resistance to apoptosis. Using a capture sequencing strategy, we discovered the B-cell relevant genes IRF8, EBF1, and TNFSF13 as novel targets for IGH deregulation. This methodology is poised to change how IGH translocations are identified in clinical settings while remaining a powerful tool to uncover the pathogenesis of B-cell malignancies.
Bohle V, Döring C, Hansmann ML, Küppers RRole of early B-cell factor 1 (EBF1) in Hodgkin lymphoma.
Leukemia. 2013; 27(3):671-9 [PubMed
] Related Publications
A hallmark of classical Hodgkin lymphoma (cHL) is that the B-cell-derived Hodgkin and Reed-Sternberg (HRS) tumor cells have largely lost the B-cell-typical gene expression program. The factors causing this 'reprogramming' of HRS cells are only partly understood. As early B-cell factor 1 (EBF1), a major B-cell transcription factor, is downregulated in HRS cells, we analyzed whether this downregulation contributes to the lost B-cell phenotype and tested the consequences of EBF1 re-expression in cHL cell lines. EBF1 re-expression caused an upregulation of B-cell genes, such as CD19, CD79A and CD79B, although the B-cell genes FOXO1 and PAX5 remained lowly expressed. The re-expression of CD19, CD79A and CD79B occurred largely without demethylation of promoter CpG motifs of these genes. In the cHL cell line L-1236 fitness decreased after EBF1 re-expression. These data show that EBF1 has the ability to reintroduce part of the B-cell signature in cHL cell lines. Loss of EBF1 expression in HRS cells therefore contributes to their lost B-cell phenotype. Notably, in the cHL cell line KM-H2 destructive mutations were found in one allele of EBF1, indicating that genetic lesions may sometimes have a role in impairing EBF1 expression.
The cellular origin of chronic lymphocytic leukemia (CLL) is still debated, although this information is critical to understanding its pathogenesis. Transcriptome analyses of CLL and the main normal B cell subsets from human blood and spleen revealed that immunoglobulin variable region (IgV) gene unmutated CLL derives from unmutated mature CD5(+) B cells and mutated CLL derives from a distinct, previously unrecognized CD5(+)CD27(+) post-germinal center B cell subset. Stereotyped V gene rearrangements are enriched among CD5(+) B cells, providing independent evidence for a CD5(+) B cell derivation of CLL. Notably, these CD5(+) B cell populations include oligoclonal expansions already found in young healthy adults, putatively representing an early phase in CLL development before the CLL precursor lesion monoclonal B cell lymphocytosis. Finally, we identified deregulated proteins, including EBF1 and KLF transcription factors, that were not detected in previous comparisons of CLL and conventional B cells.
Tijchon E, Havinga J, van Leeuwen FN, Scheijen BB-lineage transcription factors and cooperating gene lesions required for leukemia development.
Leukemia. 2013; 27(3):541-52 [PubMed
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Differentiation of hematopoietic stem cells into B lymphocytes requires the concerted action of specific transcription factors, such as RUNX1, IKZF1, E2A, EBF1 and PAX5. As key determinants of normal B-cell development, B-lineage transcription factors are frequently deregulated in hematological malignancies, such as B-cell precursor acute lymphoblastic leukemia (BCP-ALL), and affected by either chromosomal translocations, gene deletions or point mutations. However, genetic aberrations in this developmental pathway are generally insufficient to induce BCP-ALL, and often complemented by genetic defects in cytokine receptors and tyrosine kinases (IL-7Rα, CRLF2, JAK2 and c-ABL1), transcriptional cofactors (TBL1XR1, CBP and BTG1), as well as the regulatory pathways that mediate cell-cycle control (pRB and INK4A/B). Here we provide a detailed overview of the genetic pathways that interact with these B-lineage specification factors, and describe how mutations affecting these master regulators together with cooperating lesions drive leukemia development.
Genomic profiling has identified a subtype of high-risk B-progenitor acute lymphoblastic leukemia (B-ALL) with alteration of IKZF1, a gene expression profile similar to BCR-ABL1-positive ALL and poor outcome (Ph-like ALL). The genetic alterations that activate kinase signaling in Ph-like ALL are poorly understood. We performed transcriptome and whole genome sequencing on 15 cases of Ph-like ALL and identified rearrangements involving ABL1, JAK2, PDGFRB, CRLF2, and EPOR, activating mutations of IL7R and FLT3, and deletion of SH2B3, which encodes the JAK2-negative regulator LNK. Importantly, several of these alterations induce transformation that is attenuated with tyrosine kinase inhibitors, suggesting the treatment outcome of these patients may be improved with targeted therapy.
Moorman AV, Schwab C, Ensor HM, et al.IGH@ translocations, CRLF2 deregulation, and microdeletions in adolescents and adults with acute lymphoblastic leukemia.
J Clin Oncol. 2012; 30(25):3100-8 [PubMed
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PURPOSE: To determine the prevalence and prognostic impact of significant acute lymphoblastic leukemia (ALL) -related genes: CRLF2 deregulation (CRLF2-d), IGH@ translocations (IGH@-t), and deletions of CDKN2A/B, IKZF1, PAX5, ETV6, RB1, BTG1, and EBF1 in adolescents and adults.
PATIENTS AND METHODS: The cohort comprised 454 patients (age 15 to 60 years old) treated on the multicenter United Kingdom Acute Lymphoblastic Leukaemia Trial XII/Eastern Cooperative Oncology Group 2993 trial (UKALLXII/ECOG2993) with Philadelphia-negative B-cell precursor ALL. Fluorescent in situ hybridization and multiplex ligation-dependent probe amplification were used to detect these genetic alterations.
RESULTS: Twenty patients (5%) had CRLF2-d (P2RY8-CRLF2, n = 7; IGH@-CRLF2, n = 13), and 36 patients (8%) harbored an IGH@-t with a different partner gene. There was little overlap between IGH@-t, CRLF2-d, and established chromosomal abnormalities. Deletions of CDKN2A/B, IKZF1, PAX5, ETV6, RB1, BTG1, or EBF1 were prevalent with 101 (33%) of 304 patients harboring one and 102 (33%) harboring two or more alterations, occurring with varying frequency in all cytogenetic subgroups. The 5-year event-free survival, relapse-free survival (RFS), and overall survival (OS) rates for the whole cohort were 40%, 55%, and 43%, respectively. Patients with CRLF2-d, IGH@-t, and IKZF1 deletions were associated with an inferior outcome in univariate but not multivariate analysis. In particular, CRLF2-d patients had a lower RFS compared with other patients (30%), whereas those with IGH@-t or IKZF1 deletions had a lower OS (27% and 35%, respectively).
CONCLUSION: CRLF2-d and IGH@-t represent distinct subtypes of adolescent and adult ALL. Deletions of key B-cell differentiation and cell cycle control genes are highly prevalent but vary in frequency by cytogenetic subgroup. CRLF2-d, IGH@-t, and IKZF1 deletions are associated with poor outcome in adolescent and adult ALL.
BACKGROUND: Deletions of IKAROS (IKZF1) frequently occur in B-cell precursor acute lymphoblastic leukemia (B-ALL) but the mechanisms by which they influence pathogenesis are unclear. To address this issue, a cohort of 144 adult B-ALL patients (106 BCR-ABL1-positive and 38 B-ALL negative for known molecular rearrangements) was screened for IKZF1 deletions by single nucleotide polymorphism (SNP) arrays; a sub-cohort of these patients (44%) was then analyzed for gene expression profiling.
PRINCIPAL FINDINGS: Total or partial deletions of IKZF1 were more frequent in BCR-ABL1-positive than in BCR-ABL1-negative B-ALL cases (75% vs 58%, respectively, p = 0.04). Comparison of the gene expression signatures of patients carrying IKZF1 deletion vs those without showed a unique signature featured by down-regulation of B-cell lineage and DNA repair genes and up-regulation of genes involved in cell cycle, JAK-STAT signalling and stem cell self-renewal. Through chromatin immunoprecipitation and luciferase reporter assays we corroborated these findings both in vivo and in vitro, showing that Ikaros deleted isoforms lacked the ability to directly regulate a large group of the genes in the signature, such as IGLL1, BLK, EBF1, MSH2, BUB3, ETV6, YES1, CDKN1A (p21), CDKN2C (p18) and MCL1.
CONCLUSIONS: Here we identified and validated for the first time molecular pathways specifically controlled by IKZF1, shedding light into IKZF1 role in B-ALL pathogenesis.
The processes of somatic hypermutation (SHM) and class switch recombination introduced by activation-induced cytosine deaminase (AICDA) at the Immunoglobulin (Ig) loci are key steps for creating a pool of diversified antibodies in germinal center B cells (GCBs). Unfortunately, AICDA can also accidentally introduce mutations at bystander loci, particularly within the 5' regulatory regions of proto-oncogenes relevant to diffuse large B cell lymphomas (DLBCL). Since current methods for genomewide sequencing such as Exon Capture and RNAseq only target mutations in coding regions, to date non-Ig promoter SHMs have been studied only in a handful genes. We designed a novel approach integrating bioinformatics tools with next generation sequencing technology to identify regulatory loci targeted by SHM genome-wide. We observed increased numbers of SHM associated sequence variant hotspots in lymphoma cells as compared to primary normal germinal center B cells. Many of these SHM hotspots map to genes that have not been reported before as mutated, including BACH2, BTG2, CXCR4, CIITA, EBF1, PIM2, and TCL1A, etc., all of which have potential roles in B cell survival, differentiation, and malignant transformation. In addition, using BCL6 and BACH2 as examples, we demonstrated that SHM sites identified in these 5' regulatory regions greatly altered their transcription activities in a reporter assay. Our approach provides a first cost-efficient, genome-wide method to identify regulatory mutations and non-Ig SHM hotspots.
A therapeutic strategy for treating cancer is to target and eradicate cancer stem cells (CSCs) without harming their normal stem cell counterparts. The success of this approach relies on the identification of molecular pathways that selectively regulate CSC function. Using BCR-ABL-induced chronic myeloid leukemia (CML) as a disease model for CSCs, we show that BCR-ABL downregulates the Blk gene (encoding B-lymphoid kinase) through c-Myc in leukemic stem cells (LSCs) in CML mice and that Blk functions as a tumor suppressor in LSCs but does not affect normal hematopoietic stem cells (HSCs) or hematopoiesis. Blk suppresses LSC function through a pathway involving an upstream regulator, Pax5, and a downstream effector, p27. Inhibition of this Blk pathway accelerates CML development, whereas increased activity of the Blk pathway delays CML development. Blk also suppresses the proliferation of human CML stem cells. Our results show the feasibility of selectively targeting LSCs, an approach that should be applicable to other cancers.
Yan L, Ping N, Zhu M, et al.Clinical, immunophenotypic, cytogenetic, and molecular genetic features in 117 adult patients with mixed-phenotype acute leukemia defined by WHO-2008 classification.
Haematologica. 2012; 97(11):1708-12 [PubMed
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Among 4,780 consecutive adult acute lymphoblastic/myeloblastic leukemia patients, we identified 117 (2.4%) patients with mixed-phenotype acute leukemia fulfilling WHO 2008 criteria; these were classified as: Blymphoid+ myeloid (n=64), T-lymphoid+myeloid (n=38), B+T-lymphoid (n=14) and trilineage (n=1). Of 92 patients karyotyped, 59 were abnormal and were classified as: complex (22 of 92), t(9;22)(q34;q11) (14 of 92), monosomy 7 (7 of 92), polysomy 21 (7 of 92), t(v;11q23) (4 of 92), t(10;11)(p15;q21) (3 of 92), while STIL-TAL1 fusion was detected in one (T+My) patient. After investigating common acute leukemia-related mutations in 17 genes, 12 of 31 (39%) patients were found to have at least one mutation, classified with: IKZF1 deletion (4 of 31), and EZH2 (3 of 31), ASXL1 (3 of 31), ETV6 (2 of 31), NOTCH1 (1 of 31), and TET2 (1 of 31) mutations. Array-CGH revealed genomic deletions of CDKN2A (4 of 12), IKZF1 (3 of 12), MEF2C (2 of 12), BTG1 (2 of 12), together with BCOR, EBF1, K-RAS, LEF1, MBNL1, PBX3, and RUNX1 (one of 12 each). Our results indicate that mixed-phenotype acute leukemia is a complex entity with heterogeneous clinical, immunophenotypic, cytogenetic, and molecular genetic features.