Skip to content

Advertisement

  • Case Report
  • Open Access

Overexpression of the proneural transcription factor ASCL1 in chronic lymphocytic leukemia with a t(12;14)(q23.2;q32.3)

  • 1,
  • 1,
  • 1,
  • 1,
  • 2,
  • 3, 4,
  • 1,
  • 1,
  • 1,
  • 1 and
  • 1Email authorView ORCID ID profile
Molecular Cytogenetics201811:3

https://doi.org/10.1186/s13039-018-0355-7

  • Received: 4 December 2017
  • Accepted: 3 January 2018
  • Published:

Abstract

Background

Translocations of the IGH locus on 14q32.3 are present in about 8% of patients with chronic lymphocytic leukemia (CLL) and contribute to leukemogenesis by deregulating the expression of the IGH-partner genes. Identification of these genes and investigation of the downstream effects of their deregulation can reveal disease-causing mechanisms.

Case presentation

We report on the molecular characterization of a novel t(12;14)(q23.2;q32.3) in CLL. As a consequence of the rearrangement ASCL1 was brought into proximity of the IGHJ-Cμ enhancer and was highly overexpressed in the aberrant B-cells of the patient, as shown by qPCR and immunohistochemistry. ASCL1 encodes for a transcription factor acting as a master regulator of neurogenesis, is overexpressed in neuroendocrine tumors and a promising therapeutic target in small cell lung cancer (SCLC). Its overexpression has also been recently reported in acute adult T-cell leukemia/lymphoma.

To examine possible downstream effects of the ASCL1 upregulation in CLL, we compared the gene expression of sorted CD5+ cells of the translocation patient to that of CD19+ B-cells from seven healthy donors and detected 176 significantly deregulated genes (Fold Change ≥2, FDR p ≤ 0.01). Deregulation of 55 genes in our gene set was concordant with at least two studies comparing gene expression of normal and CLL B-lymphocytes. INSM1, a well-established ASCL1 target in the nervous system and SCLC, was the gene with the strongest upregulation (Fold Change = 209.4, FDR p = 1.37E-4).

INSM1 encodes for a transcriptional repressor with extranuclear functions, implicated in neuroendocrine differentiation and overexpressed in the majority of neuroendocrine tumors. It was previously shown to be induced in CLL cells but not in normal B-cells upon treatment with IL-4 and to be overexpressed in CLL cells with unmutated versus mutated IGHV genes. Its role in CLL is still unexplored.

Conclusion

We identified ASCL1 as a novel IGH-partner gene in CLL. The neural transcription factor was strongly overexpressed in the patient’s CLL cells. Microarray gene expression analysis revealed the strong upregulation of INSM1, a prominent ASCL1 target, which was previously shown to be induced in CLL cells upon IL-4 treatment. We propose further investigation of the expression and potential role of INSM1 in CLL.

Keywords

  • ASCL1 overexpression
  • INSM1
  • IGH translocation
  • Chronic lymphocytic leukemia
  • Expression microarray

Background

Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of small clonal mature B-lymphocytes in blood, bone marrow (BM) and lymphatic tissues [1]. CLL cells present with a distinctive immunophenotype defined by the co-expression of CD5, CD19 and CD23. The levels of surface immunoglobulin, CD79b and CD20 are low compared to normal B-lymphocytes [2]. The clinical course of CLL is heterogeneous, ranging from long-term survival without the need of treatment to rapid progression despite early and aggressive therapy.

Recurrent cytogenetic lesions are found in more than 80% of the CLL patients and have a prognostic value. Deletions are mostly found at 13q, followed by 11q, 17p and 6q, while trisomy 12 is the most common numerical aberration [3, 4]. Although translocations occur in about 32–34% of the CLL cases, recurrent chromosomal translocations are rare events, found in about 5% of the patients [5, 6]. Most translocation breakpoints cluster on 13q14 followed by the IGH locus on 14q32.3 [4, 5]. A recent review of 18 studies estimated the overall frequency of IGH rearrangements in CLL to be about 8%, with reported frequencies varying between 2 and 26% [7].

IGH rearrangements can occur during IGH locus remodeling as a result of VDJ recombination, somatic hypermutation or class switch recombination. All these procedures take place in the course of B-cell development and involve the generation and re-ligation of double strand breaks [8]. IGH locus breakpoints cluster in the joining (IGHJ) and switch regions (IGHS) [9], although breakpoints in the variable (IGHV) and diversity (IGHD) regions have also been described [10]. In most instances, the biological consequence of the rearrangement is the deregulation of the partner gene, due to its juxtaposition to one of the IGH enhancers, reviewed by Willis and Dyer [11]. Except of the t(14;18)(q32;q21), immunoglobulin gene translocations are associated with a poor prognosis in CLL [7].

Here we report on the molecular characterization of a novel t(12;14)(q23.2;q32.3) in a patient with CLL. A search in the Mitelman Database of Chromosome Aberrations and gene fusions in cancer [12] for translocations involving the 12q23 region in CLL patients revealed three further cases reported in the literature [6, 13, 14]. Molecular characterization was performed in only one of these cases and revealed a fusion of the CHST11 gene on 12q23.3 to the IGH locus [13].

Case presentation

Our patient was a 58-year old female, diagnosed with CLL in 2002. Abnormal lymphocytes showed expression of CD5, CD19, CD20, CD22, CD23 and immunoglobulin kappa light chain by flow cytometry. Ubiquitous enlarged lymph nodes were detected. The patient was asymptomatic. First line treatment was required 2003 due to increasing leukocytosis and lymphocytosis accompanied by advancing anemia and thrombocytopenia. The patient was treated with chlorambucil and prednisone (Knospe protocol) according to local standards and therapeutic possibilities at that time. After achieving a partial remission persisting approximately one year, the patient was retreated with continuous chlorambucil for one month but showed no response. Four cycles of oral fludarabine were administered achieving a partial remission for four years. The following two relapses of the disease were treated again with fludarabine, of which the latter course was mainly due to patient’s preference. After documenting resistance to fludarabine the patient agreed to administration of five cycles rituximab in combination with bendamustine. A partial remission could be achieved. Rituximab and bendamustine were used for treating the following relapse 1.5 years later, achieving a partial remission for another eight months. Afterwards the patient received ibrutinib within a clinical trial, but showed progression of disease after only four months of treatment. Massive progression of lymphadenopathy was apparent at that time. Therefore, a lymph node biopsy was done showing a diffuse infiltration with small lymphocytic cells partially resembling centroblasts or immunoblasts, though transformation to an aggressive lymphoma could not be demonstrated. According to the clinical behavior of the disease, rituximab plus CHOP were administered but progression occurred after three cycles of treatment. Alemtuzumab was then administered achieving stabilization of the disease for another year. Ultimately, the patient was treated with lenalidomide but showed no significant response and died 2014 due to pneumonia. Informed consent for studies performed and for publication of the results was obtained from the patient. All methods used are described in detail in Additional file 1.

Patient material was first sent to our laboratory eight years after the initial diagnosis of CLL. In the next four years, karyotyping and FISH studies were performed seven times in intervals of six to twelve months. The detailed cytogenetic findings in the seven samples of the patient, analyzed between 2010 and 2014, are summarized in Table 1. Consistent findings in all patient probes included the t(12;14)(q23.2;q32.3), a partial trisomy 12 due to duplication of der(12) chromosome (Fig. 1a) and a submicroscopic deletion of the 13q14 region. Signal splitting of the Cytocell IGH Breakapart probe confirmed the involvement of the IGH locus on chromosome 14 in the translocation (Fig. 1b). The duplication of der(12) indicates that the t(12;14)(q23.2;q32.3) preceded trisomy 12. Since trisomy 12 is considered to be an early driver clonal event in CLL [15], we propose that the translocation occurred early in CLL evolution. Nevertheless, it is not possible to experimentally confirm that, since no sample was available at the time of diagnosis.
Table 1

Summary of the cytogenetic findings in the seven samples of the patient

Date

Cytogenetic Findings

Bone Marrow (BM) Infiltration, Therapy

27.05.2010

47,XX,t(12;14)(q23.2;q32.3),+der(12)t(12;14)[9]/46,XX[11].

nuc ish(ATM,TP53)×2[204],(D12Z1x3,D13S319x1,LAMP1×2)[158/230],(5’IGHx3,3’IGH×2)(5’IGH sep 3’IGHx1)[167/216]

80% BM infiltration, fludarabine resistance, thrombopenia, therapy switch to rituximab and bendamustine

21.03.2011

47,XX,t(12;14)(q23.2;q32.3),+der(12)t(12;14)[7].ish der(12)t(12;14)(q23.2;q32.3)x2(5’IGH+).

nuc ish(D12Z1x3,D13S319x1,LAMP1x2)[91/212], (5’IGHx3,3’IGHx2)(5’IGH sep 3’IGHx1)[91/223]

Thrombocytopenia, 40% BM infiltration

24.10.2011

47,XX,t(12;14)(q23.2;q32.3),+der(12)t(12;14)[17]/46,XX[5]

Rituximab and bendamustine

14.03.2012

47,XX,t(12;14)(q23.2;q32.3),+der(12)t(12;14)[19]/46,XX[1]

95% BM infiltration

11.03.2013

45~47,XX,del(3)(p21),t(12;14)(q23.2;q32.3),+der(12)t(12;14),-13,add(17)(p11.2)[cp8]/46,XX[3].

nuc ish(ATMx2,TP53x1)[121/169],(D12Z3x3,D13S319x0,LAMP1x1)[146/217]/

(D12Z3x3,D13S319x1,LAMP1x1)[17/217]

85% BM infiltration, progression despite therapy with Ibrutinib, lymphadenopathy

03.09.2013

47,XX,t(12;14)(q23.2;q32.3),+der(12)t(12;14)[5]/46,idem,del(3)(p21),-13,add(17)(p11.2)[3]/46,XX[3]

80% BM infiltration, Alemtuzumab

09.01.2014

47,XX,t(12;14)(q23.2;q32.3),+der(12)t(12;14)[7]/46,idem,del(3)(p21),-13,add(17)(p11.2)[2]/46,XX[6]

96% BM infiltration, sample for expression microarray received

Clinical findings and therapy at the same time points are also stated

Fig. 1
Fig. 1

a Karyotype of the patient displaying the t(12;14)(q23.2;q32.3). Arrows mark the translocation breakpoint regions on the derivative chromosomes. Note that der(12) is duplicated, leading to a partial trisomy 12. b Karyotype evolution (about three years later). Additional aberrations include a del(3)(p21), monosomy 13 and add(17)(p11). For detailed information see also Table 1. c FISH with the Cytocell IGH Breakapart probe on metaphase and interphase nuclei. The normal chromosome 14 generates a red-green fusion fluorescence signal. Der(14) yields only a red fluorescence signal with the distal green-labeled probe being translocated on der(12). A second green fluorescence signal is present due to the der(12) duplication. On the upper right side, a normal interphase with two red-green fusion signals is shown, next to an interphase bearing the translocation (lower right). A white arrow marks the fusion signal from the normal chromosome 14

Sequencing of LDI-PCR-generated IGHJ bands varying from the expected germline bands revealed a productive VDJ recombination with an unmutated V1–69 gene (100% sequence homology) fused to D3–3 and J5 sequences and a D-J recombination between D2–21 and J5 on the other allele. Sequencing of the aberrant IGHS bands revealed sequences from chromosome 12 integrated into the Switch μ (Sμ) region. A second round of sequencing with a reverse primer from chromosome 14 (IGH der12 Rv) was necessary to read over the breakpoint on der(12), which was located 86.5 kbp downstream of the achaete-scute family bHLH transcription factor 1 (ASCL1) gene. Primer sequences are listed in (Additional file 2: Table S1). The IGHJ- enhancer was translocated in the proximity of ASCL1, while the more distal gene C12orf42 was translocated to der(14). The breakpoint on der(14) was localized within the pentameric repeat region of Sμ. There were no deletions or insertions of sequences at the breakpoints of both chromosomes (Fig. 2).
Fig. 2
Fig. 2

Translocation breakpoints and derivative chromosome composition. Horizontal gray arrows indicate the transcriptional direction of the depicted genes. Vertical black arrows indicate breakpoints (BP). a Breakpoint region on chromosome 12. The breakpoint took place 86.5 kb distal of the ASCL1 gene. b The IGH locus on chromosome 14. The breakpoint took place within the pentameric repeat region of Switch μ. Dots indicate the IGH enhancer elements. c Composition of der(12) and sequence around the breakpoint. The enhancer element is part of the translocated IGH sequence and is juxtaposed to ASCL1. d der(14) and breakpoint sequence. The C12orf42 gene is translocated to chromosome 14

The expression of ASCL1 in the BM of the patient bearing the translocation (90% infiltration) was compared to that in normal and CLL BM samples (mean infiltration >70%). CLL samples were subdivided in four groups according to their cytogenetic findings (Table 2). ASCL1 was highly overexpressed in the sample of the patient bearing the translocation as opposed to all other groups with average fold change (FC) values greater than 5600 in all samples (ANOVA p-value = 5.12E-10) (Fig. 3a). Immunohistochemistry with a monoclonal anti-ASCL1 antibody on peripheral blood cytospins of the patient and two CLL control samples confirmed the ASCL1 overexpression at the protein level (Fig. 3b and c).
Table 2

CLL patient samples used for ASCL1 quantification by qPCR

 

Normal cytogenetics

Monoallelic Del(13q)

Biallelic Del(13q)

Trisomy 12

Sample number

7

8

6

9

IGHV hypermutated/unmutated

3/4

4/4

3/3

6/3

Mean aberrant cells in BM

81%

88%

88%

72%

Distribution according to cytogenetic findings, IGHV mutation status and mean bone marrow (BM) infiltration

Fig. 3
Fig. 3

Validation of the ASCL1 overexpression. a Comparison of the BM expression of ASCL1 between the CLL patient with the t(12;14) translocation and healthy controls as well as CLL with normal karyotype, mono- and biallelic del(13) and trisomy 12 respectively. Results are displayed as log2 fold change. HB2M was used as housekeeping control. Comparisons of the ASCL1 expression in the patient versus all other groups were highly significant (ANOVA p-value = 5.12E-10). Comparisons between normal BM and all other groups were not significant. b Immunohistochemistry for ASCL1 on a peripheral blood cytospin of the patient bearing the t(12;14). Note the strong nuclear reaction in the center. In contrast to that a sample from a B-CLL control (c) showed no antibody reaction. Nuclei are counterstained with hematoxylin

ASCL1, also known as hASH1 or mASH1, is the human homolog of the Drosophila achaete-scute complex. It encodes for a basic pioneer helix-loop-helix transcription factor (TF), which is a master regulator of vertebrate neurogenesis [16]. In order to further explore the possible downstream effects of the ASCL1 upregulation in the aberrant B-cells of the patient, we compared the gene expression of these cells to that of sorted B-cells from seven healthy donors, using the GeneChip® PrimeView™ Human Gene Expression Array (Affymetrix, Santa Clara, CA). We found 176 significantly deregulated genes (FC ≥ 2, FDR p ≤ 0.01) (Additional file 3: Figure S1) and (Additional file 4: Table S2). Deregulation of 55 genes in our gene set was concordant with at least two CLL expression studies comparing CLL cells to peripheral CD19+ B-lymphocytes of healthy individuals (see also Additional file 4) [1720].

We then focused on the genes with the strongest deregulation in our gene set (FC ≥ 10, FDR p ≤ 0.001) (Table 3). Seven of the top 18 deregulated genes (ABCA9, KCNJ11, FHDC1, KSR2, EBF1 and RGS2) were part of the above-mentioned CLL gene expression signature. The deregulation of three further genes from this list (RGS1, APP, GABRB2 and FGF2) was concordant with CLL versus normal comparisons from the Oncomine Database [2124]. Among the residual eight highly deregulated genes the overexpression of ASCL1 and also PAH, localized 40 kbp proximal to the ASCL1 locus, could be explained by their proximity to the IGH enhancer due to the translocation. PAH encodes for phenylalanine hydroxylase, an enzyme involved in phenylalanine catabolism. To our knowledge, no oncogenic properties have been assigned to the PAH gene so far. Binding of ASCL1 on promoter sequences of the MRO, EDNRB and RNF150 genes has been demonstrated by ChIP in adult hippocampus-derived neural stem cells [25]. The overexpression of GLDN and PAX9 has not been previously described in CLL and these genes are also not listed among the direct ASCL1 targets. INSM1, the gene with the highest upregulation and the third most significant in our gene set, is a well- established direct ASCL1 transcriptional target in neural and neuroendocrine tissue as well as in SCLC [2628].
Table 3

Highly deregulated genes in the CLL cells of the translocation patient versus normal B-cells (FC > 10, FDR p < 0.01)

Gene Symbol

Fold Change

FDR p-value

Deregulation in CLL

Reference

INSM1

209.42

0.000137

  

ASCL1

202.32

0.000029

  

ABCA9

118.18

0.000114

overexpressed

[17] [19] [20]

PAH

84.87

0.000166

  

MRO

82.52

0.000408

  

GABRB2

42.47

0.000495

overexpressed

[21]

PAX9

38.71

0.000800

  

RNF150

27.45

0.000748

  

FHDC1

25.51

0.000537

overexpressed

[17] [19] [20]

KCNJ11

20.52

0.000458

overexpressed

[19] [20]

KSR2

20.37

0.000748

overexpressed

[17] [20]

FGF2

18.37

0.000748

overexpressed

[22]

GLDN

18.02

0.000881

  

EDNRB

12.07

0.000495

  

APP

−21.43

0.000489

underexpressed

[21]

RGS2

−24.38

0.000902

underexpressed

[17] [19]

EBF1

−61.42

0.000976

underexpressed

[17] [19]

RGS1

−98.36

0.000970

underexpressed

[17] [23]

Information about gene deregulation in CLL and relevant references are shown

Discussion and conclusions

We report on a CLL patient bearing a t(12;14)(q23.2;q32.3). So far, molecular characterization of one CLL case with a t(12;14)(q23;q32) has been reported in the literature [13]. The chromosome 12 breakpoint was located about 1.4 Mb distal to that found in our patient and disrupted the CHST11 gene encoding for a Golgi-associated sulfotransferase. The translocation probably led to the expression of truncated versions of the CHST11 protein with altered cellular distribution [13].

In the present case, the translocation led to the overexpression of ASCL1 and the more proximal PAH gene in the aberrant B–cells of the patient. ASCL1 plays a role in the development of lung neuroendocrine cells [29], thyroid C cells [30] and adrenal chromaffin cells [31], is overexpressed in neuroendocrine tumors [32] and is a promising therapeutic target in SCLC [27, 33]. Several transcriptional targets of ASCL1 have been identified in normal neural development and in cancer cells with functions in NOTCH signaling, cell proliferation and differentiation [25, 27, 3337]. It is remarkable that ASCL1 acts as a pioneer TF, having the ability to access nucleosomal DNA, promote its opening and accessibility to other TFs [36, 38, 39] and enable reprogramming non-neural cells to induced neurons [40, 41].

According to a meta-analysis of microarray data in the Oncomine database, ASCL1 was one of the top 1% overexpressed genes in acute adult T-cell leukemia/lymphoma (FC: 3.76, p = 3.43E-5) [24, 42, 43], while reduced expression of ASCL1 was reported in diffuse large B-cell, primary effusion and mantle cell lymphoma [24, 43]. The biological consequences of the above observations are currently unknown. According to the same database, a study comparing the expression profiles of normal and CLL peripheral mononuclear cells reported underexpression of ASCL1 in CLL (FC = −3.07 p = 5.31E-4) [24, 44]. Nevertheless, this could not be confirmed by a study with a larger patient cohort, comparing the same cell types [21, 24]. According to our qPCR results, there were no significant ASCL1 expression differences between normal BM and that of various CLL cytogenetic subsets (mean BM infiltration >70%) (Fig. 3).

Global gene expression analysis of the patient’s CLL cells versus B-cells from healthy donors revealed a CLL gene expression signature comprising of 55 genes, concordant with published results of at least two studies comparing the same cell types. INSM1, the gene with the highest fold change in the patient, is a prominent ASCL1 target [26, 27, 33, 35, 45]. It is likely that its strong deregulation in the B-cells of our patient is a result of the ASCL1 overexpression. Nevertheless, since the targets of a transcription factor can vary depending on the cellular context, it is not possible to exactly predict which genes would actually be regulated by ASCL1 in a B-cell without performing functional studies.

INSM1 encodes for a conserved zinc-finger transcriptional repressor [46], which controls neuroendocrine differentiation and is overexpressed in the majority of neuroendocrine tumors [26, 47]. Notably, INSM1 is also able to exert its function by directly influencing signaling pathways through protein-protein binding. For example, its association with cyclin D1 (CCND1) has been reported to cause cell cycle lengthening without triggering apoptosis [48].

Little is known about the potential role of INSM1 in CLL. According to Liao et al. 2015 INSM1 expression is higher in CLL cells with unmutated versus that with mutated IGHV genes [17]. Ruiz-Lafuente et al. reported induction of INSM1 in CLL cells but not in normal B-cells upon treatment with IL-4 [17]. Since IL-4 stimulation is part of the stromal interactions that protect CLL cells from apoptosis, genes induced by IL-4 in CLL cells could contribute to their survival [17]. The INSM1 overexpression in the peripheral B-cells of our patient, possibly taking place due to the ASCL1 overexpression, could provide a further hint for a potential role of INSM1 in CLL, thus we propose the further examination of its expression and possible role in CLL pathogenesis.

Abbreviations

BM: 

Bone marrow

CLL: 

Chronic lymphocytic leukemia

FC: 

Fold change

SCLC: 

Small cell lung cancer

TF: 

Transcription factor

Declarations

Acknowledgements

We thank Gerlinde Laukoter and Margarete Aichberger for performance of FACS analysis and cell sorting.

Funding

Not applicable.

Availability of data and materials

Authors declare that all relevant data are included in the article and the additional files.

Authors’ contributions

TM designed the study, performed experiments, analyzed the data and wrote the manuscript. MR performed RNA isolation for microarray experiments and contributed to data analysis. SH performed optimization of RNA isolation from sorted lymphocytes. JB performed qPCR experiments. SB provided the clinical description of the CLL patient. HCB performed and evaluated immunohistochemistry experiments. RM and WK contributed to experiment design and analysis. ME and SD contributed to the cytogenetic analysis of CLL patients. GW initiated the project, performed study design, data analysis and coordinated the works. All authors read and approved the final manuscript.

Ethics approval and consent to participate

Gene expression analysis in CLL patients was approved by the ethics and research committee of the Ordensklinikum Linz, Barmherzige Schwestern (No. 2709).

Written informed consent for experimental work was obtained by the patient.

Consent for publication

Written informed consent for publication of the results was obtained by the patient.

Competing interests

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Authors’ Affiliations

(1)
Laboratory for Molecular Biology and Tumor Cytogenetics, Department of Internal Medicine I, Ordensklinikum Linz GmbH Barmherzige Schwestern, Seilerstaette 4, 4010 Linz, Austria
(2)
Department for Internal Medicine IV, Klinikum Wels-Grieskirchen, Grieskirchner Str. 42, 4600 Wels, Austria
(3)
Department of Pathology, Ordensklinikum Linz GmbH Barmherzige Schwestern, Seilerstaette 4, 4010 Linz, Austria
(4)
Present Address: Institute for Pathology and Neuropathology, University Hospital Tuebingen, Liebermeisterstraße 8, 72076 Tuebingen, Germany

References

  1. Zenz T, Mertens D, Küppers R, Dohner H, Stilgenbauer S. From pathogenesis to treatment of chronic lymphocytic leukaemia. Nat Rev Cancer. 2010;10(1):37–50.View ArticlePubMedGoogle Scholar
  2. Hallek M, Cheson BD, Catovsky D, Caligaris-Cappio F, Dighiero G, Dohner H, et al. Guidelines for the diagnosis and treatment of chronic lymphocytic leukemia: a report from the international workshop on chronic lymphocytic leukemia updating the National Cancer Institute-working group 1996 guidelines. Blood. 2008;111(12):5446–56.View ArticlePubMedPubMed CentralGoogle Scholar
  3. Döhner H, Stilgenbauer S, Benner A, Leupolt E, Krober A, Bullinger L, et al. Genomic aberrations and survival in chronic lymphocytic leukemia. N Engl J Med. 2000;343(26):1910–6.View ArticlePubMedGoogle Scholar
  4. Haferlach C, Dicker F, Schnittger S, Kern W, Haferlach T. Comprehensive genetic characterization of CLL: a study on 506 cases analysed with chromosome banding analysis, interphase FISH, IgV(H) status and immunophenotyping. Leukemia. 2007;21(12):2442–51.View ArticlePubMedGoogle Scholar
  5. Baliakas P, Iskas M, Gardiner A, Davis Z, Plevova K, Nguyen-Khac F, et al. Chromosomal translocations and karyotype com plexity in chronic lymphocytic leukemia: a systematic reappraisal of classic cytogenetic data. Am J Hematol. 2014;89(3):249–55.View ArticlePubMedGoogle Scholar
  6. Mayr C, Speicher MR, Kofler DM, Buhmann R, Strehl J, Busch R, et al. Chromosomal translocations are associated with poor prognosis in chronic lymphocytic leukemia. Blood. 2006;107(2):742–51.View ArticlePubMedGoogle Scholar
  7. De Braekeleer M, Tous C, Gueganic N, LEB MJ, Basinko A, Morel F, et al. Immunoglobulin gene translocations in chronic lymphocytic leukemia: a report of 35 patients and review of the literature. Mol Clin Oncol. 2016;4(5):682–94.View ArticlePubMedPubMed CentralGoogle Scholar
  8. Küppers R, Dalla-Favera R. Mechanisms of chromosomal translocations in B cell lymphomas. Oncogene. 2001;20(40):5580–94.View ArticlePubMedGoogle Scholar
  9. Saglio G, Grazia Borrello M, Guerrasio A, Sozzi G, Serra A, di Celle PF, et al. Preferential clustering of chromosomal breakpoints in Burkitt's lymphomas and L3 type acute lymphoblastic leukemias with a t(8;14) translocation. Genes Chromosomes Cancer. 1993;8(1):1–7.View ArticlePubMedGoogle Scholar
  10. Kuipers J, Vaandrager JW, Weghuis DO, Pearson PL, Scheres J, Lokhorst HM, et al. Fluorescence in situ hybridization analysis shows the frequent occurrence of 14q32.3 rearrangements with involvement of immunoglobulin switch regions in myeloma cell lines. Cancer Genet Cytogenet. 1999;109(2):99–107.View ArticlePubMedGoogle Scholar
  11. Willis TG, Dyer MJ. The role of immunoglobulin translocations in the pathogenesis of B-cell malignancies. Blood. 2000;96(3):808–22.PubMedGoogle Scholar
  12. Mitelman F, Johansson B, Mertens F: Mitelman Database of Chromosome Aberrations and Gene Fusions in Cancer http://cgap.nci.nih.gov/Chromosomes/Mitelman (2018). Accessed 03 Jan 2018.
  13. Schmidt HH, Dyomin VG, Palanisamy N, Itoyama T, Nanjangud G, Pirc-Danoewinata H, et al. Deregulation of the carbohydrate (chondroitin 4) sulfotransferase 11 (CHST11) gene in a B-cell chronic lymphocytic leukemia with a t(12;14)(q23;q32). Oncogene. 2004;23(41):6991–6.View ArticlePubMedGoogle Scholar
  14. Brejcha M, Stoklasova M, Brychtova Y, Panovska A, Stepanovska K, Vankova G, et al. Clonal evolution in chronic lymphocytic leukemia detected by fluorescence in situ hybridization and conventional cytogenetics after stimulation with CpG oligonucleotides and interleukin-2: a prospective analysis. Leuk Res. 2014;38(2):170–5.View ArticlePubMedGoogle Scholar
  15. Landau DA, Carter SL, Stojanov P, McKenna A, Stevenson K, Lawrence MS, et al. Evolution and impact of subclonal mutations in chronic lymphocytic leukemia. Cell. 2013;152(4):714–26.View ArticlePubMedPubMed CentralGoogle Scholar
  16. Vasconcelos FF, Castro DS. Transcriptional control of vertebrate neurogenesis by the proneural factor Ascl1. Front Cell Neurosci. 2014;8:412.View ArticlePubMedPubMed CentralGoogle Scholar
  17. Ruiz-Lafuente N, Alcaraz-Garcia MJ, Sebastian-Ruiz S, Gomez-Espuch J, Funes C, Moraleda JM, et al. The gene expression response of chronic lymphocytic leukemia cells to IL-4 is specific, depends on ZAP-70 status and is differentially affected by an NFkappaB inhibitor. PLoS One. 2014;9(10):e109533.View ArticlePubMedPubMed CentralGoogle Scholar
  18. Jelinek DF, Tschumper RC, Stolovitzky GA, Iturria SJ, Tu Y, Lepre J, et al. Identification of a global gene expression signature of B-chronic lymphocytic leukemia. Mol Cancer Res. 2003;1(5):346–61.PubMedGoogle Scholar
  19. Ferreira PG, Jares P, Rico D, Gomez-Lopez G, Martinez-Trillos A, Villamor N, et al. Transcriptome characterization by RNA sequencing identifies a major molecular and clinical subdivision in chronic lymphocytic leukemia. Genome Res. 2014;24(2):212–26.View ArticlePubMedPubMed CentralGoogle Scholar
  20. Liao W, Jordaan G, Nham P, Phan RT, Pelegrini M, Sharma S. Gene expression and splicing alterations analyzed by high throughput RNA sequencing of chronic lymphocytic leukemia specimens. BMC Cancer. 2015;15:714.View ArticlePubMedPubMed CentralGoogle Scholar
  21. Haferlach T, Kohlmann A, Wieczorek L, Basso G, Kronnie GT, Bene MC, et al. Clinical utility of microarray-based gene expression profiling in the diagnosis and subclassification of leukemia: report from the international microarray innovations in leukemia study group. J Clin Oncol. 2010;28(15):2529–37.View ArticlePubMedPubMed CentralGoogle Scholar
  22. Basso K, Margolin AA, Stolovitzky G, Klein U, Dalla-Favera R, Califano A. Reverse engineering of regulatory networks in human B cells. Nat Genet. 2005;37(4):382–90.View ArticlePubMedGoogle Scholar
  23. Rosenwald A, Alizadeh AA, Widhopf G, Simon R, Davis RE, Yu X, et al. Relation of gene expression phenotype to immunoglobulin mutation genotype in B cell chronic lymphocytic leukemia. J Exp Med. 2001;194(11):1639–47.View ArticlePubMedPubMed CentralGoogle Scholar
  24. Rhodes DR, Kalyana-Sundaram S, Mahavisno V, Varambally R, Yu J, Briggs BB, et al. Oncomine 3.0: genes, pathways, and networks in a collection of 18,000 cancer gene expression profiles. Neoplasia. 2007;9(2):166–80.View ArticlePubMedPubMed CentralGoogle Scholar
  25. Andersen J, Urban N, Achimastou A, Ito A, Simic M, Ullom K, et al. A transcriptional mechanism integrating inputs from extracellular signals to activate hippocampal stem cells. Neuron. 2014;83(5):1085–97.View ArticlePubMedPubMed CentralGoogle Scholar
  26. Lan MS, Breslin MB. Structure, expression, and biological function of INSM1 transcription factor in neuroendocrine differentiation. FASEB J. 2009;23(7):2024–33.View ArticlePubMedPubMed CentralGoogle Scholar
  27. Borromeo MD, Savage TK, Kollipara RK, He M, Augustyn A, Osborne JK, et al. ASCL1 and NEUROD1 reveal heterogeneity in pulmonary neuroendocrine tumors and regulate distinct genetic programs. Cell Rep. 2016;16(5):1259–72.View ArticlePubMedPubMed CentralGoogle Scholar
  28. Jia S, Wildner H, Birchmeier C. Insm1 controls the differentiation of pulmonary neuroendocrine cells by repressing Hes1. Dev Biol. 2015;Google Scholar
  29. Borges M, Linnoila RI, van de Velde HJ, Chen H, Nelkin BD, Mabry M, et al. An achaete-scute homologue essential for neuroendocrine differentiation in the lung. Nature. 1997;386(6627):852–5.View ArticlePubMedGoogle Scholar
  30. Lanigan TM, DeRaad SK, Russo AF. Requirement of the MASH-1 transcription factor for neuroendocrine differentiation of thyroid C cells. J Neurobiol. 1998;34(2):126–34.View ArticlePubMedGoogle Scholar
  31. Huber K, Brühl B, Guillemot F, Olson EN, Ernsberger U, Unsicker K. Development of chromaffin cells depends on MASH1 function. Development. 2002;129(20):4729–38.PubMedGoogle Scholar
  32. Ball DW, Azzoli CG, Baylin SB, Chi D, Dou S, Donis-Keller H, et al. Identification of a human achaete-scute homolog highly expressed in neuroendocrine tumors. Proc Natl Acad Sci U S A. 1993;90(12):5648–52.View ArticlePubMedPubMed CentralGoogle Scholar
  33. Augustyn A, Borromeo M, Wang T, Fujimoto J, Shao C, Dospoy PD, et al. ASCL1 is a lineage oncogene providing therapeutic targets for high-grade neuroendocrine lung cancers. Proc Natl Acad Sci U S A. 2014;111(41):14788–93.View ArticlePubMedPubMed CentralGoogle Scholar
  34. Borromeo MD, Meredith DM, Castro DS, Chang JC, Tung KC, Guillemot F, et al. A transcription factor network specifying inhibitory versus excitatory neurons in the dorsal spinal cord. Development. 2014;141(14):2803–12.View ArticlePubMedPubMed CentralGoogle Scholar
  35. Castro DS, Martynoga B, Parras C, Ramesh V, Pacary E, Johnston C, et al. A novel function of the proneural factor Ascl1 in progenitor proliferation identified by genome-wide characterization of its targets. Genes Dev. 2011;25(9):930–45.View ArticlePubMedPubMed CentralGoogle Scholar
  36. Raposo AA, Vasconcelos FF, Drechsel D, Marie C, Johnston C, Dolle D, et al. Ascl1 coordinately regulates gene expression and the chromatin landscape during neurogenesis. Cell Rep. 2015;10(9):1544–56.Google Scholar
  37. Jiang T, Collins BJ, Jin N, Watkins DN, Brock MV, Matsui W, et al. Achaete-scute complex homologue 1 regulates tumor-initiating capacity in human small cell lung cancer. Cancer Res. 2009;69(3):845–54.View ArticlePubMedPubMed CentralGoogle Scholar
  38. Wapinski OL, Vierbuchen T, Qu K, Lee QY, Chanda S, Fuentes DR, et al. Hierarchical mechanisms for direct reprogramming of fibroblasts to neurons. Cell. 2013;155(3):621–35.View ArticlePubMedGoogle Scholar
  39. Wapinski OL, Lee QY, Chen AC, Li R, Corces MR, Ang CE, et al. Rapid chromatin switch in the direct reprogramming of fibroblasts to neurons. Cell Rep. 2017;20(13):3236–47.View ArticlePubMedPubMed CentralGoogle Scholar
  40. Vierbuchen T, Ostermeier A, Pang ZP, Kokubu Y, Sudhof TC, Wernig M. Direct conversion of fibroblasts to functional neurons by defined factors. Nature. 2010;463(7284):1035–41.View ArticlePubMedPubMed CentralGoogle Scholar
  41. Chanda S, Ang CE, Davila J, Pak C, Mall M, Lee QY, et al. Generation of induced neuronal cells by the single reprogramming factor ASCL1. Stem Cell Reports. 2014;3(2):282–96.View ArticlePubMedPubMed CentralGoogle Scholar
  42. Choi YL, Tsukasaki K, O'Neill MC, Yamada Y, Onimaru Y, Matsumoto K, et al. A genomic analysis of adult T-cell leukemia. Oncogene. 2007;26(8):1245–55.View ArticlePubMedGoogle Scholar
  43. Wang CY, Shahi P, Huang JT, Phan NN, Sun Z, Lin YC, et al. Systematic analysis of the achaete-scute complex-like gene signature in clinical cancer patients. Mol Clin Oncol. 2017;6(1):7–18.View ArticlePubMedGoogle Scholar
  44. Haslinger C, Schweifer N, Stilgenbauer S, Dohner H, Lichter P, Kraut N, et al. Microarray gene expression profiling of B-cell chronic lymphocytic leukemia subgroups defined by genomic aberrations and VH mutation status. J Clin Oncol. 2004;22(19):3937–49.View ArticlePubMedGoogle Scholar
  45. Jacob J, Storm R, Castro DS, Milton C, Pla P, Guillemot F, et al. Insm1 (IA-1) is an essential component of the regulatory network that specifies monoaminergic neuronal phenotypes in the vertebrate hindbrain. Development. 2009;136(14):2477–85.View ArticlePubMedPubMed CentralGoogle Scholar
  46. Goto Y, De Silva MG, Toscani A, Prabhakar BS, Notkins AL, Lan MSA. Novel human insulinoma-associated cDNA, IA-1, encodes a protein with "zinc-finger" DNA-binding motifs. J Biol Chem. 1992;267(21):15252–7.PubMedGoogle Scholar
  47. Rosenbaum JN, Guo Z, Baus RM, Werner H, Rehrauer WM, Lloyd RV. INSM1: A Novel Immunohistochemical and Molecular marker for neuroendocrine and Neuroepithelial neoplasms. Am J Clin Pathol. 2015;144(4):579–91.View ArticlePubMedGoogle Scholar
  48. Zhang T, Liu WD, Saunee NA, Breslin MB, Lan MS. Zinc finger transcription factor INSM1 interrupts cyclin D1 and CDK4 binding and induces cell cycle arrest. J Biol Chem. 2009;284(9):5574–81.View ArticlePubMedPubMed CentralGoogle Scholar

Copyright

Advertisement