RUNX1

Gene Summary

Gene:RUNX1; runt-related transcription factor 1
Aliases: AML1, CBFA2, EVI-1, AMLCR1, PEBP2aB, AML1-EVI-1
Location:21q22.3
Summary:Core binding factor (CBF) is a heterodimeric transcription factor that binds to the core element of many enhancers and promoters. The protein encoded by this gene represents the alpha subunit of CBF and is thought to be involved in the development of normal hematopoiesis. Chromosomal translocations involving this gene are well-documented and have been associated with several types of leukemia. Three transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:runt-related transcription factor 1
HPRD
Source:NCBIAccessed: 16 March, 2015

Ontology:

What does this gene/protein do?
Show (35)

Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 16 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.

  • Cell Differentiation
  • FISH
  • Cancer Gene Expression Regulation
  • Taiwan
  • Proto-Oncogene Proteins c-kit
  • fms-Like Tyrosine Kinase 3
  • Infant
  • Fusion Proteins, bcr-abl
  • Mutation
  • Sequence Homology, Nucleic Acid
  • RUNX1
  • Acute Myeloid Leukaemia
  • Chromosome 21
  • Leukemic Gene Expression Regulation
  • Core Binding Factor Alpha 2 Subunit
  • Oncogene Fusion Proteins
  • Repressor Proteins
  • Proto-Oncogene Proteins
  • Valproic Acid
  • Telomere
  • Oligonucleotide Array Sequence Analysis
  • ETV6
  • Point Mutation
  • Homologous Transplantat
  • Translocation
  • Karyotyping
  • Neoplasm Proteins
  • Adolescents
  • DNA Mutational Analysis
  • Leukaemia
  • Stomach Cancer
  • Acute Lymphocytic Leukaemia
  • Precursor B-Cell Lymphoblastic Leukemia-Lymphoma
  • Phenotype
  • Gene Expression Profiling
  • Chromosome Aberrations
  • U937 Cells
  • EVI1
  • Childhood Cancer
  • Neoplastic Cell Transformation
  • Chromosome 8
  • Oncogenes
  • Rhabdomyosarcoma
Tag cloud generated 16 March, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (6)

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 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
Acute Myeloid Leukaemia (AML) t(8;21)(q22;q22) in Acute Myeloid Leukemia
The t(8;21) translocation is the most frequent cytogenetic abnormality in acute myeloid leukaemia (AML). The translocation fuses the RUNX1 (CBFA2, AML1) gene on chromosome 21q to the RUNX1T1 (CBFA2T1, ETO) gene on chromosome 8q. The resulting fusion gene AML1-ETO occurs more frequently, though not exclusively, in the AML-M2 sub-type. In a series of 64 AML cases Andrieu et al (1996) detected the fusion in 3% (1/32) of M1 patients compared to 8/32 (25%) with M2. It is detected in approximately 20% of adult and 40% of paediatric patients with AML-M2.
Acute Myeloid Leukaemia (AML)t(3;21)(q26;q22) in Secondary Leukaemia / MDS
Rubin et al (1990) reported a recurring chromosomal abnormality of t(3;21)(q26;q22)in therapy-related myelodysplastic syndrome and acute myeloid leukemia
Leukaemiat(3;12)(p13;q22) in Leukaemia

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

Latest Publications: RUNX1 (cancer-related)

Illendula A, Pulikkan JA, Zong H, et al.
Chemical biology. A small-molecule inhibitor of the aberrant transcription factor CBFβ-SMMHC delays leukemia in mice.
Science. 2015; 347(6223):779-84 [PubMed] Related Publications
Acute myeloid leukemia (AML) is the most common form of adult leukemia. The transcription factor fusion CBFβ-SMMHC (core binding factor β and the smooth-muscle myosin heavy chain), expressed in AML with the chromosome inversion inv(16)(p13q22), outcompetes wild-type CBFβ for binding to the transcription factor RUNX1, deregulates RUNX1 activity in hematopoiesis, and induces AML. Current inv(16) AML treatment with nonselective cytotoxic chemotherapy results in a good initial response but limited long-term survival. Here, we report the development of a protein-protein interaction inhibitor, AI-10-49, that selectively binds to CBFβ-SMMHC and disrupts its binding to RUNX1. AI-10-49 restores RUNX1 transcriptional activity, displays favorable pharmacokinetics, and delays leukemia progression in mice. Treatment of primary inv(16) AML patient blasts with AI-10-49 triggers selective cell death. These data suggest that direct inhibition of the oncogenic CBFβ-SMMHC fusion protein may be an effective therapeutic approach for inv(16) AML, and they provide support for transcription factor targeted therapy in other cancers.

Mansour MR, Abraham BJ, Anders L, et al.
Oncogene regulation. An oncogenic super-enhancer formed through somatic mutation of a noncoding intergenic element.
Science. 2014; 346(6215):1373-7 [PubMed] Related Publications
In certain human cancers, the expression of critical oncogenes is driven from large regulatory elements, called super-enhancers, that recruit much of the cell's transcriptional apparatus and are defined by extensive acetylation of histone H3 lysine 27 (H3K27ac). In a subset of T-cell acute lymphoblastic leukemia (T-ALL) cases, we found that heterozygous somatic mutations are acquired that introduce binding motifs for the MYB transcription factor in a precise noncoding site, which creates a super-enhancer upstream of the TAL1 oncogene. MYB binds to this new site and recruits its H3K27 acetylase-binding partner CBP, as well as core components of a major leukemogenic transcriptional complex that contains RUNX1, GATA-3, and TAL1 itself. Additionally, most endogenous super-enhancers found in T-ALL cells are occupied by MYB and CBP, which suggests a general role for MYB in super-enhancer initiation. Thus, this study identifies a genetic mechanism responsible for the generation of oncogenic super-enhancers in malignant cells.

Ashworth J, Bernard B, Reynolds S, et al.
Structure-based predictions broadly link transcription factor mutations to gene expression changes in cancers.
Nucleic Acids Res. 2014; 42(21):12973-83 [PubMed] Free Access to Full Article Related Publications
Thousands of unique mutations in transcription factors (TFs) arise in cancers, and the functional and biological roles of relatively few of these have been characterized. Here, we used structure-based methods developed specifically for DNA-binding proteins to systematically predict the consequences of mutations in several TFs that are frequently mutated in cancers. The explicit consideration of protein-DNA interactions was crucial to explain the roles and prevalence of mutations in TP53 and RUNX1 in cancers, and resulted in a higher specificity of detection for known p53-regulated genes among genetic associations between TP53 genotypes and genome-wide expression in The Cancer Genome Atlas, compared to existing methods of mutation assessment. Biophysical predictions also indicated that the relative prevalence of TP53 missense mutations in cancer is proportional to their thermodynamic impacts on protein stability and DNA binding, which is consistent with the selection for the loss of p53 transcriptional function in cancers. Structure and thermodynamics-based predictions of the impacts of missense mutations that focus on specific molecular functions may be increasingly useful for the precise and large-scale inference of aberrant molecular phenotypes in cancer and other complex diseases.

Chou SC, Tang JL, Hou HA, et al.
Prognostic implication of gene mutations on overall survival in the adult acute myeloid leukemia patients receiving or not receiving allogeneic hematopoietic stem cell transplantations.
Leuk Res. 2014; 38(11):1278-84 [PubMed] Related Publications
Several gene mutations have been shown to provide clinical implications in patients with acute myeloid leukemia (AML). However, the prognostic impact of gene mutations in the context of allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains unclear. We retrospectively evaluated the clinical implications of 8 gene mutations in 325 adult AML patients; 100 of them received allo-HSCT and 225 did not. The genetic alterations analyzed included NPM1, FLT3-ITD, FLT3-TKD, CEBPA, RUNX1, RAS, MLL-PTD, and WT1. In patients who did not receive allo-HSCT, older age, higher WBC count, higher lactate dehydrogenase level, unfavorable karyotype, and RUNX1 mutation were significantly associated with poor overall survival (OS), while CEBPA double mutation (CEBPA(double-mut)) and NPM1(mut)/FLT3-ITD(neg) were associated with good outcome. However, in patients who received allo-HSCT, only refractory disease status at the time of HSCT and unfavorable karyotype were independent poor prognostic factors. Surprisingly, RUNX1 mutation was an independent good prognostic factor for OS in multivariate analysis. The prognostic impact of FLT3-ITD or NPM1(mut)/FLT3-ITD(neg) was lost in this group of patients receiving allo-HSCT, while CEBPA(double-mut) showed a trend to be a good prognostic factor. In conclusion, allo-HSCT can ameliorate the unfavorable influence of some poor-risk gene mutations in AML patients. Unexpectedly, the RUNX1 mutation showed a favorable prognostic impact in the context of allo-HSCT. These results need to be confirmed by further studies with more AML patients.

Schmidt M, Rinke J, Schäfer V, et al.
Molecular-defined clonal evolution in patients with chronic myeloid leukemia independent of the BCR-ABL status.
Leukemia. 2014; 28(12):2292-9 [PubMed] Related Publications
To study clonal evolution in chronic myeloid leukemia (CML), we searched for BCR-ABL-independent gene mutations in both Philadelphia chromosome (Ph)-negative and Ph-positive clones in 29 chronic-phase CML patients by targeted deep sequencing of 25 genes frequently mutated in myeloid disorders. Ph-negative clones were analyzed in 14 patients who developed clonal cytogenetic abnormalities in Ph-negative cells during treatment with tyrosine kinase inhibitors (TKI). Mutations were detected in 6/14 patients (43%) affecting the genes DNMT3A, EZH2, RUNX1, TET2, TP53, U2AF1 and ZRSR2. In two patients, the mutations were also found in corresponding Ph-positive diagnostic samples. To further investigate Ph-positive clones, 15 randomly selected CML patients at diagnosis were analyzed. Somatic mutations additional to BCR-ABL were found in 5/15 patients (33%) affecting ASXL1, DNMT3A, RUNX1 and TET2. Analysis of individual hematopoietic colonies at diagnosis revealed that most mutations were part of the Ph-positive clone. In contrast, deep sequencing of subsequent samples during TKI treatment revealed one DNMT3A mutation in Ph-negative cells that was also present in Ph-positive cells at diagnosis, implying that the mutation preceded the BCR-ABL rearrangement. In summary, BCR-ABL-independent gene mutations were frequently found in Ph-negative and Ph-positive clones of CML patients and may be considered as important cofactors in the clonal evolution of CML.

Shima T, Miyamoto T, Kikushige Y, et al.
The ordered acquisition of Class II and Class I mutations directs formation of human t(8;21) acute myelogenous leukemia stem cell.
Exp Hematol. 2014; 42(11):955-65.e1-5 [PubMed] Related Publications
The cellular properties of leukemia stem cells (LSCs) are achieved at least through Class I and Class II mutations that generate signals for enhanced proliferation and impaired differentiation, respectively. Here we show that in t(8;21) acute myelogenous leukemia (AML), hematopoietic stem cells (HSCs) transform into LSCs via definitively-ordered acquisition of Class II (AML1/ETO) and then Class I (c-KIT mutant) abnormalities. Six t(8;21) AML patients with c-KIT mutants maintaining > 3 years of complete remission were analyzed. At diagnosis, all single LSCs had both AML1/ETO and c-KIT mutations. However, in remission, 16 out of 1,728 CD34(+)CD38(-) HSCs and 89 out of 7,187 single HSC-derived myeloerythroid colonies from these patients had AML1/ETO, whose breakpoints were identical to those found in LSCs. These cells had wild-type c-KIT, which expressed AML1/ETO at a low level, and could differentiate into mature blood cells, suggesting that they may be the persistent preleukemic stem cells. Microarray analysis suggested that mutated c-KIT signaling provides LSCs with enhanced survival and proliferation. Thus, in t(8;21) AML, the acquisition of AML1/ETO is not sufficient, and the subsequent upregulation of AML1/ETO and the additional c-KIT mutant signaling are critical steps for transformation into LSCs.

Al-Kzayer LF, Sakashita K, Al-Jadiry MF, et al.
Frequent coexistence of RAS mutations in RUNX1-mutated acute myeloid leukemia in Arab Asian children.
Pediatr Blood Cancer. 2014; 61(11):1980-5 [PubMed] Related Publications
BACKGROUND: RUNX1 mutation plays an important role in adult leukemic transformation. However, its contribution to the development of childhood leukemia remains unclear. In the present study, we analyzed point mutations of RUNX1 gene in children and adolescents with acute myeloid leukemia (AML) from Iraq and Jordan.
PROCEDURE: Bone marrow and/or peripheral blood samples were collected from 178 patients of Arab Asian ethnicity (aged ≤17 years) newly diagnosed with AML: 145 samples from Iraq and 33 samples from Jordan. Direct DNA sequencing was performed on six genes including RUNX1 gene (exons 3-8).
RESULTS: RUNX1 point mutations were identified in 10 (5.6%) of 178 patients. One patient possessed biallelic mutations of RUNX1 gene. C-terminal area was the predominant site of RUNX1 mutations (eight in C-terminal and two in N-terminal). Patients with RUNX1 mutations were significantly older than those with wild-type of the gene. Additionally, AML M0 subtype was more frequently found in patients with RUNX1 mutations. Both RUNX1 mutations and RAS mutations were identified in 4 of 10 children. Three patients with RUNX1 mutation had FLT3-ITD. On the other hand, 36 (21.4%) and 25 (14.9%) of 168 patients with wild-type of the gene had a RAS mutation and FLT3-ITD, respectively. Eight of 10 patients with RUNX1 mutations died of hematological relapse.
CONCLUSION: The incidence of RUNX1 mutations in Arab Asian children and adolescents with AML was 5.6%. Further studies are required to clarify whether RAS mutations contribute to the development of pediatric AML associated with RUNX1 mutations.

Kwiatkowski N, Zhang T, Rahl PB, et al.
Targeting transcription regulation in cancer with a covalent CDK7 inhibitor.
Nature. 2014; 511(7511):616-20 [PubMed] Free Access to Full Article Related Publications
Tumour oncogenes include transcription factors that co-opt the general transcriptional machinery to sustain the oncogenic state, but direct pharmacological inhibition of transcription factors has so far proven difficult. However, the transcriptional machinery contains various enzymatic cofactors that can be targeted for the development of new therapeutic candidates, including cyclin-dependent kinases (CDKs). Here we present the discovery and characterization of a covalent CDK7 inhibitor, THZ1, which has the unprecedented ability to target a remote cysteine residue located outside of the canonical kinase domain, providing an unanticipated means of achieving selectivity for CDK7. Cancer cell-line profiling indicates that a subset of cancer cell lines, including human T-cell acute lymphoblastic leukaemia (T-ALL), have exceptional sensitivity to THZ1. Genome-wide analysis in Jurkat T-ALL cells shows that THZ1 disproportionally affects transcription of RUNX1 and suggests that sensitivity to THZ1 may be due to vulnerability conferred by the RUNX1 super-enhancer and the key role of RUNX1 in the core transcriptional regulatory circuitry of these tumour cells. Pharmacological modulation of CDK7 kinase activity may thus provide an approach to identify and treat tumour types that are dependent on transcription for maintenance of the oncogenic state.

Thota S, Viny AD, Makishima H, et al.
Genetic alterations of the cohesin complex genes in myeloid malignancies.
Blood. 2014; 124(11):1790-8 [PubMed] Free Access to Full Article Related Publications
Somatic cohesin mutations have been reported in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). To account for the morphologic and cytogenetic diversity of these neoplasms, a well-annotated cohort of 1060 patients with myeloid malignancies including MDS (n = 386), myeloproliferative neoplasms (MPNs) (n = 55), MDS/MPNs (n = 169), and AML (n = 450) were analyzed for cohesin gene mutational status, gene expression, and therapeutic and survival outcomes. Somatic cohesin defects were detected in 12% of patients with myeloid malignancies, whereas low expression of these genes was present in an additional 15% of patients. Mutations of cohesin genes were mutually exclusive and mostly resulted in predicted loss of function. Patients with low cohesin gene expression showed similar expression signatures as those with somatic cohesin mutations. Cross-sectional deep-sequencing analysis for clonal hierarchy demonstrated STAG2, SMC3, and RAD21 mutations to be ancestral in 18%, 18%, and 47% of cases, respectively, and each expanded to clonal dominance concordant with disease transformation. Cohesin mutations were significantly associated with RUNX1, Ras-family oncogenes, and BCOR and ASXL1 mutations and were most prevalent in high-risk MDS and secondary AML. Cohesin defects were associated with poor overall survival (27.2 vs 40 months; P = .023), especially in STAG2 mutant MDS patients surviving >12 months (median survival 35 vs 50 months; P = .017).

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).

Migas AA, Mishkova OA, Ramanouskaya TV, et al.
RUNX1T1/MTG8/ETO gene expression status in human t(8;21)(q22;q22)-positive acute myeloid leukemia cells.
Leuk Res. 2014; 38(9):1102-10 [PubMed] Related Publications
The RUNX1-RUNX1T1 fusion gene, a product of the nonhomologous balanced translocation t(8;21)(q22;q22), is a complex genetic locus. We performed extensive bioinformatic analysis of transcription initiation as well as transcription termination sites in this locus and predicted a number of different RUNX1T1 transcripts. To confirm and quantify the RUNX1T1 gene expression, we analyzed samples from seven acute myeloid leukemia (AML) patients and from the Kasumi-1 cell line. We found variable activity of the four predicted RUNX1T1 promoters located downstream of the chromosome breakpoint. Nineteen alternative RUNX1T1 transcripts were identified by sequencing at least seventeen of which predictably can be translated into functional proteins. While the RUNX1T1 gene is not expressed in normal hematopoietic cells, it may participate in t(8;21)(q22;q22)-dependent leukemic transformation due to its multiple interactions in cell regulatory network particularly through synergistic or antagonistic effects in relation to activity of RUNX1-RUNX1T1 fusion gene.

Ferrari N, Mohammed ZM, Nixon C, et al.
Expression of RUNX1 correlates with poor patient prognosis in triple negative breast cancer.
PLoS One. 2014; 9(6):e100759 [PubMed] Free Access to Full Article Related Publications
The RUNX1 transcription factor is widely recognised for its tumour suppressor effects in leukaemia. Recently a putative link to breast cancer has started to emerge, however the function of RUNX1 in breast cancer is still unknown. To investigate if RUNX1 expression was important to clinical outcome in primary breast tumours a tissue microarray (TMA) containing biopsies from 483 patients with primary operable invasive ductal breast cancer was stained by immunohistochemistry. RUNX1 was associated with progesterone receptor (PR)-positive tumours (P<0.05), more tumour CD4+(P<0.05) and CD8+(P<0.01) T-lymphocytic infiltrate, increased tumour CD138+plasma cell (P<0.01) and more CD68+macrophage infiltrate (P<0.001). RUNX1 expression did not influence outcome of oestrogen receptor (ER)-positive or HER2-positive disease, however on univariate analysis a high RUNX1 protein was significantly associated with poorer cancer-specific survival in patients with ER-negative (P<0.05) and with triple negative (TN) invasive breast cancer (P<0.05). Furthermore, multivariate Cox regression analysis of cancer-specific survival showed a trend towards significance in ER-negative patients (P<0.1) and was significant in triple negative patients (P<0.05). Of relevance, triple negative breast cancer currently lacks good biomarkers and patients with this subtype do not benefit from the option of targeted therapy unlike patients with ER-positive or HER2-positive disease. Using multivariate analysis RUNX1 was identified as an independent prognostic marker in the triple negative subgroup. Overall, our study identifies RUNX1 as a new prognostic indicator correlating with poor prognosis specifically in the triple negative subtype of human breast cancer.

Wang TY, Huang YP, Ma P
Correlations of common polymorphism of EVI-1 gene targeted by miRNA-206/133b with the pathogenesis of breast cancer.
Tumour Biol. 2014; 35(9):9255-62 [PubMed] Related Publications
The aim of this study was to identify the correlations of a common polymorphism (rs6774494 A > G) in the EVI-1 gene targeted by micro-RNA (miRNA)-206/133b with the pathogenesis of breast cancer (BC). A total of 196 unrelated ethnic Han Chinese women diagnosed with primary BC were consecutively recruited and 200 healthy controls were randomly selected from the same population-based cohort. Direct PCR sequencing assay was used to detection of rs6774494 A > G polymorphism in the EVI-1 gene. Real-time quantitative PCR (RT-PCR) analysis was performed to verify the alterations of the EVI1 messenger RNA (mRNA) levels. Kaplan-Meier analysis was used to investigate and to estimate the survival outcomes for each endpoint. All statistical analyses were performed with SPSS software (version 18.0, SPSS, Chicago, IL). Our results demonstrated that the carriers of EVI-1 AG genotype were more likely to develop BC when compared with the EVI-1 GG genotype (P = 0.034, OR = 1.26, 95% CI = 1.02 ∼ 1.57). In addition, it was found that patients with the G (AG + GG) allele of EVI-1 genetic variants were associated with higher risk of BC compared with the EVI-1 AA genotype (OR = 1.26, 95% CI = 1.02 ∼ 1.54, P = 0.028). The results of a subgroup analysis stratified by menopause revealed that in female post-menopause subgroup patients with the EVI-1 G allele were correlated with a higher risk of BC than those with the EVI-1 AA genotype (OR = 1.31, 95% CI = 1.00 ∼ 1.72, P = 0.054). Kaplan-Meier analyses suggested that carriers of the G allele (AG + GG) were associated with poorer overall survival (OS) and progression-free survival (PFS) compared with those with AA genotype (OS P = 0.042; PFS P = 0.036, respectively). The correlation analysis showed that EVI-1 mRNA levels were negatively associated with miRNA-206/133b levels in the carriers of the G allele (AG + GG) (r = -1.274, P < 0.05). Our findings provide evidence that the EVI-1 rs6774494 G > A polymorphism targeted by miRNA-206/133b may contribute to the pathogenesis of BC.

Herold T, Metzeler KH, Vosberg S, et al.
Isolated trisomy 13 defines a homogeneous AML subgroup with high frequency of mutations in spliceosome genes and poor prognosis.
Blood. 2014; 124(8):1304-11 [PubMed] Related Publications
In acute myeloid leukemia (AML), isolated trisomy 13 (AML+13) is a rare chromosomal abnormality whose prognostic relevance is poorly characterized. We analyzed the clinical course of 34 AML+13 patients enrolled in the German AMLCG-1999 and SAL trials and performed exome sequencing, targeted candidate gene sequencing and gene expression profiling. Relapse-free (RFS) and overall survival (OS) of AML+13 patients were inferior compared to other ELN Intermediate-II patients (n=855) (median RFS, 7.8 vs 14.1 months, P = .006; median OS 9.3 vs. 14.8 months, P = .004). Besides the known high frequency of RUNX1 mutations (75%), we identified mutations in spliceosome components in 88%, including SRSF2 codon 95 mutations in 81%. Recurring mutations were detected in ASXL1 (44%) and BCOR (25%). Two patients carried mutations in CEBPZ, suggesting that CEBPZ is a novel recurrently mutated gene in AML. Gene expression analysis revealed a homogeneous expression profile including upregulation of FOXO1 and FLT3 and downregulation of SPRY2. This is the most comprehensive clinical and biological characterization of AML+13 to date, and reveals a striking clustering of lesions in a few genes, defining AML+13 as a genetically homogeneous subgroup with alterations in a few critical cellular pathways. Clinicaltrials.gov identifiers: AMLCG-1999: NCT00266136; AML96: NCT00180115; AML2003: NCT00180102; and AML60+: NCT00893373.

Zhang L, Cao Z, Ruan M, et al.
Monitoring the AML1/ETO fusion transcript to predict outcome in childhood acute myeloid leukemia.
Pediatr Blood Cancer. 2014; 61(10):1761-6 [PubMed] Related Publications
BACKGROUND: To determine the prognostic significance of the detection of the minimal residual disease (MRD) in children with AML1/ETO AML, we compared the results of reverse-transcription polymerase chain reaction (RT-PCR) and quantitative reverse-transcription polymerase chain reaction (RQ-PCR).
PROCEDURE: Between January 2006 and February 2013, 70 patients (≤16 years of age) with AML1/ETO AML were included in our study. Bone marrow samples were evaluated using by both RT-PCR and RQ-PCR assays. AML1/ETO transcripts were normalized to 10(5) ABL copies.
RESULTS: When treated with fewer than four courses of therapy, no association was found between positive RT-PCR results and relapse. After four courses of therapy, a positive RT-PCR result was correlated with a probability of relapse. After induction chemotherapy, a >1.8 log reduction in AML1/ETO transcripts in BM determined by RQ-PCR may represent a subgroup of patients at low risk for relapse. MRD levels after consolidation (Courses 2 and 3) were also informative.
CONCLUSION: Both RT-PCR and RQ-PCR can be used to detect MRD in childhood AML1/ETO AML. RQ-PCR can identify patients who are at high risk of relapse earlier than can RT-PCR.

Tian J, Rui K, Wang S
Roles of miRNAs in regulating the differentiation and maturation of myeloid-derived suppressor cells.
Med Hypotheses. 2014; 83(2):151-3 [PubMed] Related Publications
Myeloid-derived suppressor cells (MDSCs) accumulate in tumor-bearing hosts and play an essential role in tumor-associated immunosuppression, which hampers effective immunotherapeutic approaches. MicroRNAs (miRNAs) are short noncoding RNAs that negatively regulate target gene expression at the posttranscriptional level. miRNAs are involved in regulating cell proliferation, differentiation and maturation, and abnormal expression and function of miRNAs are recognized in various human diseases. Accumulating evidence shows that various miRNAs modulate the development and differentiation of myeloid cells, which implies their possible role in the differentiation of MDSCs into mature myeloid cells. Our recent studies have found that the classical myeloid differentiation related gene runt-related transcription factor 1 (Runx1) and target nuclear factor 1/A (NFI-A) are modulated during the differentiation and maturation of MDSCs while six miRNAs are found to possibly regulate these two targets by miRNA array analysis. Thus, we hypothesize that the predicted miRNAs may modulate the target genes to regulate the differentiation and maturation of MDSCs. Further studies will provide a novel potential approach for tumor immunotherapy.

Sasca D, Hähnel PS, Szybinski J, et al.
SIRT1 prevents genotoxic stress-induced p53 activation in acute myeloid leukemia.
Blood. 2014; 124(1):121-33 [PubMed] Related Publications
SIRT1 is an important regulator of cellular stress response and genomic integrity. Its role in tumorigenesis is controversial. Whereas sirtuin 1 (SIRT1) can act as a tumor suppressor in some solid tumors, increased expression has been demonstrated in many cancers, including hematologic malignancies. In chronic myeloid leukemia, SIRT1 promoted leukemia development, and targeting SIRT1 sensitized chronic myeloid leukemia progenitors to tyrosine kinase inhibitor treatment. In this study, we investigated the role of SIRT1 in acute myeloid leukemia (AML). We show that SIRT1 protein, but not RNA levels, is overexpressed in AML samples harboring activating mutations in signaling pathways. In FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD)(+)-cells protein, expression of SIRT1 is regulated by FLT3 kinase activity. In addition, SIRT1 function is modulated via the ATM-DBC1-SIRT1 axis in a FLT3-ITD-dependent manner. In murine leukemia models driven by MLL-AF9 or AML1-ETO coexpressing FLT3-ITD, SIRT1 acts as a safeguard to counteract oncogene-induced stress, and leukemic blasts become dependent on SIRT1 activity. Pharmacologic targeting or RNAi-mediated knockdown of SIRT1 inhibited cell growth and sensitized AML cells to tyrosine kinase inhibitor treatment and chemotherapy. This effect was a result of the restoration of p53 activity. Our data suggest that targeting SIRT1 represents an attractive therapeutic strategy to overcome primary resistance in defined subsets of patients with AML.

Prange KH, Singh AA, Martens JH
The genome-wide molecular signature of transcription factors in leukemia.
Exp Hematol. 2014; 42(8):637-50 [PubMed] Related Publications
Transcription factors control expression of genes essential for the normal functioning of the hematopoietic system and regulate development of distinct blood cell types. During leukemogenesis, aberrant regulation of transcription factors such as RUNX1, CBFβ, MLL, C/EBPα, SPI1, GATA, and TAL1 is central to the disease. Here, we will discuss the mechanisms of transcription factor deregulation in leukemia and how in recent years next-generation sequencing approaches have helped to elucidate the molecular role of many of these aberrantly expressed transcription factors. We will focus on the complexes in which these factors reside, the role of posttranslational modification of these factors, their involvement in setting up higher order chromatin structures, and their influence on the local epigenetic environment. We suggest that only comprehensive knowledge on all these aspects will increase our understanding of aberrant gene expression in leukemia as well as open new entry points for therapeutic intervention.

Mok MM, Du L, Wang CQ, et al.
RUNX1 point mutations potentially identify a subset of early immature T-cell acute lymphoblastic leukaemia that may originate from differentiated T-cells.
Gene. 2014; 545(1):111-6 [PubMed] Related Publications
The RUNX1/AML1 gene is among the most frequently mutated genes in human leukaemia. However, its association with T-cell acute lymphoblastic leukaemia (T-ALL) remains poorly understood. In order to examine RUNX1 point mutations in T-ALL, we conducted an amplicon-based deep sequencing in 65 Southeast Asian childhood patients and 20 T-ALL cell lines, and detected RUNX1 mutations in 6 patients (9.2%) and 5 cell lines (25%). Interestingly, RUNX1-mutated T-ALL cases seem to constitute a subset of early immature T-ALL that may originate from differentiated T-cells. This result provides a deeper insight into the mechanistic basis for leukaemogenesis.

Xiong Z, Yu H, Ding Y, et al.
RNA sequencing reveals upregulation of RUNX1-RUNX1T1 gene signatures in clear cell renal cell carcinoma.
Biomed Res Int. 2014; 2014:450621 [PubMed] Free Access to Full Article Related Publications
In the past few years, therapies targeted at the von Hippel-Lindau (VHL) and hypoxia-inducible factor (HIF) pathways, such as sunitinib and sorafenib, have been developed to treat clear cell renal cell carcinoma (ccRCC). However, the majority of patients will eventually show resistance to antiangiogenesis therapies. The purpose of our study was to identify novel pathways that could be potentially used as targets for new therapies. Whole transcriptome sequencing (RNA-Seq) was conducted on eight matched tumor and adjacent normal tissue samples. A novel RUNX1-RUNX1T1 pathway was identified which was upregulated in ccRCC through gene set enrichment analysis (GSEA). We also confirmed the findings based on previously published gene expression microarray data. Our data shows that upregulated of the RUNX1-RUNX1T1 gene set maybe an important factor contributing to the etiology of ccRCC.

de Sousa VP, Chaves CB, Huguenin JF, et al.
ERM/ETV5 and RUNX1/AML1 expression in endometrioid adenocarcinomas of endometrium and association with neoplastic progression.
Cancer Biol Ther. 2014; 15(7):888-94 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
The majority of endometrioid endometrial carcinomas (EEC) is diagnosed at stage I. Among these, 30% present myometrial invasion (stage IB), which is associated with tumor spread and relapse after primary treatment. Although an increased expression of RUNX1/AML1 and ERM/ETV5 in EEC have been suggested to be associated with early events of myometrial infiltration, there is no data regarding its expression along the evolution of EEC and possible associations with other clinicopathological parameters. Therefore, ERM/ETV5 and RUNX1/AML1 protein and gene expression profiles were assessed in different EEC stages to evaluate their role in endometrial carcinogenesis. RUNX1/AML1 and ERM/ETV5 proteins were analyzed by immunohistochemistry in 219 formalin fixed paraffin embedded endometrioid tumors and in 12 normal atrophic and proliferative endometrium samples. RUNX1/AML1 and ERM/ETV5 genes expression were analyzed by RT-qPCR. RUNX1/AML1 and ERM/ETV5 expression were decreased with increasing EEC stage, with a positive correlation between protein and gene expression for ERM/ETV5, but not for RUNX1/AML1. Both proteins were present in the nucleus of the tumor cells, whereas RUNX1/AML1, but not ERM/ETV5, was expressed in 7 out of 12 normal endometrial samples, with its expression being restricted to the cytoplasm of the positive cells. We concluded that there is a higher expression of ERM/ETV5 in early stages of EEC, whereas there seems to be a RUNX1/AML1 translocation from cytoplasm to nucleus in EEC neoplastic transformation.

Walsh KM, de Smith AJ, Welch TC, et al.
Genomic ancestry and somatic alterations correlate with age at diagnosis in Hispanic children with B-cell acute lymphoblastic leukemia.
Am J Hematol. 2014; 89(7):721-5 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
Hispanic children have a higher incidence of acute lymphoblastic leukemia (ALL) than non-Hispanic whites but tend to be diagnosed at older ages. In genome-wide association studies, Native American ancestry and polymorphisms in six genes have been associated with ALL risk. In multivariable regression models, we investigated whether genomic ancestry, inherited risk SNPs, or acquired somatic alterations were associated with differences in age at diagnosis in Hispanic children with B-cell ALL. Genome-wide array data were used to estimate each participant's percent membership in the three Hispanic ancestral populations: Native American, African, and European. Each 20% increase in European ancestry was associated with a six month younger age at diagnosis (95% CI = 0.36-11.6 months, P = 0.037). Correspondingly, each 20% increase in Native American ancestry was associated with a six-month older age at diagnosis (P = 0.037). Both the TEL-AML1 translocation and high-hyperdiploidy were associated with younger age at diagnosis (24.4 months, P = 2.0 x 10(-4) and 12.4 months, P = 0.011, respectively), while CDKN2A and IKZF1 deletions were associated with older age at diagnosis (19.7 months, P = 7.0 x 10(-4) and 18.1 months, P = 0.012, respectively). No associations with age at diagnosis were observed for RAS mutation, PAX5 deletion or for known heritable risk alleles in IKZF1, CDKN2A, PIP4K2A, GATA3, ARID5B, or CEBPE. Because younger age at diagnosis is associated with improved treatment outcomes for children with ALL, the effect of European ancestry on ALL survival may be mediated by its effect on age at diagnosis, or by proxy, its association with more treatable molecular subtypes of ALL.

Wang H, Li W, Guo R, et al.
An intragenic long noncoding RNA interacts epigenetically with the RUNX1 promoter and enhancer chromatin DNA in hematopoietic malignancies.
Int J Cancer. 2014; 135(12):2783-94 [PubMed] Related Publications
RUNX1, a master regulator of hematopoiesis, is the most commonly perturbed target of chromosomal abnormalities in hematopoietic malignancies. The t(8;21) translocation is found in 30-40% of cases of acute myeloid leukemia (AML). Recent whole-exome sequencing also reveals mutations and deletions of RUNX1 in some solid tumors. We describe a RUNX1-intragenic long noncoding RNA RUNXOR that is transcribed as unspliced transcript from an upstream overlapping promoter. RUNXOR was upregulated in AML samples and in response to Ara-C treatment in vitro. RUNXOR utilizes its 3'-terminal fragment to directly interact with the RUNX1 promoter and enhancers and participates in the orchestration of an intrachromosomal loop. The 3' region of RUNXOR also participates in long-range interchromosomal interactions with chromatin regions that are involved in multiple RUNX1 translocations. These data suggest that RUNXOR noncoding RNA may function as a previously unidentified candidate component that is involved in chromosomal translocation in hematopoietic malignancies.

Eisfeld AK, Schwind S, Patel R, et al.
Intronic miR-3151 within BAALC drives leukemogenesis by deregulating the TP53 pathway.
Sci Signal. 2014; 7(321):ra36 [PubMed] Article available free on PMC after 01/07/2015 Related Publications
The BAALC/miR-3151 locus on chromosome 8q22 contains both the BAALC gene (for brain and acute leukemia, cytoplasmic) and miR-3151, which is located in intron 1 of BAALC. Older acute myeloid leukemia (AML) patients with high expression of both miR-3151 and the BAALC mRNA transcript have a low survival prognosis, and miR-3151 and BAALC expression is associated with poor survival independently of each other. We found that miR-3151 functioned as the oncogenic driver of the BAALC/miR-3151 locus. Increased production of miR-3151 reduced the apoptosis and chemosensitivity of AML cell lines and increased leukemogenesis in mice. Disruption of the TP53-mediated apoptosis pathway occurred in leukemia cells overexpressing miR-3151 and the miR-3151 bound to the 3' untranslated region of TP53. In contrast, BAALC alone had only limited oncogenic activity. We found that miR-3151 contains its own regulatory element, thus partly uncoupling miR-3151 expression from that of the BAALC transcript. Both genes were bound and stimulated by a complex of the transcription factors SP1 and nuclear factor κB (SP1/NF-κB). Disruption of SP1/NF-κB binding reduced both miR-3151 and BAALC expression. However, expression of only BAALC, but not miR-3151, was stimulated by the transcription factor RUNX1, suggesting a mechanism for the partly discordant expression of miR-3151 and BAALC observed in AML patients. Similar to the AML cells, in melanoma cell lines, overexpression of miR-3151 reduced the abundance of TP53, and knockdown of miR-3151 increased caspase activity, whereas miR-3151 overexpression reduced caspase activity. Thus, this oncogenic miR-3151 may also have a role in solid tumors.

Sakurai M, Kunimoto H, Watanabe N, et al.
Impaired hematopoietic differentiation of RUNX1-mutated induced pluripotent stem cells derived from FPD/AML patients.
Leukemia. 2014; 28(12):2344-54 [PubMed] Related Publications
Somatic mutation of RUNX1 is implicated in various hematological malignancies, including myelodysplastic syndrome and acute myeloid leukemia (AML), and previous studies using mouse models disclosed its critical roles in hematopoiesis. However, the role of RUNX1 in human hematopoiesis has never been tested in experimental settings. Familial platelet disorder (FPD)/AML is an autosomal dominant disorder caused by germline mutation of RUNX1, marked by thrombocytopenia and propensity to acute leukemia. To investigate the physiological function of RUNX1 in human hematopoiesis and pathophysiology of FPD/AML, we derived induced pluripotent stem cells (iPSCs) from three distinct FPD/AML pedigrees (FPD-iPSCs) and examined their defects in hematopoietic differentiation. By in vitro differentiation assays, FPD-iPSCs were clearly defective in the emergence of hematopoietic progenitors and differentiation of megakaryocytes, and overexpression of wild-type (WT)-RUNX1 reversed most of these phenotypes. We further demonstrated that overexpression of mutant-RUNX1 in WT-iPSCs did not recapitulate the phenotype of FPD-iPSCs, showing that the mutations were of loss-of-function type. Taken together, this study demonstrated that haploinsufficient RUNX1 allele imposed cell-intrinsic defects on hematopoietic differentiation in human experimental settings and revealed differential impacts of RUNX1 dosage on human and murine megakaryopoiesis. FPD-iPSCs will be a useful tool to investigate mutant RUNX1-mediated molecular processes in hematopoiesis and leukemogenesis.

Spirin PV, Lebedev TD, Orlova NN, et al.
Silencing AML1-ETO gene expression leads to simultaneous activation of both pro-apoptotic and proliferation signaling.
Leukemia. 2014; 28(11):2222-8 [PubMed] Related Publications
The t(8;21)(q22;q22) rearrangement represents the most common chromosomal translocation in acute myeloid leukemia (AML). It results in a transcript encoding for the fusion protein AML1-ETO (AE) with transcription factor activity. AE is considered to be an attractive target for treating t(8;21) leukemia. However, AE expression alone is insufficient to cause transformation, and thus the potential of such therapy remains unclear. Several genes are deregulated in AML cells, including KIT that encodes a tyrosine kinase receptor. Here, we show that AML cells transduced with short hairpin RNA vector targeting AE mRNAs have a dramatic decrease in growth rate that is caused by induction of apoptosis and deregulation of the cell cycle. A reduction in KIT mRNA levels was also observed in AE-silenced cells, but silencing KIT expression reduced cell growth but did not induce apoptosis. Transcription profiling of cells that escape cell death revealed activation of a number of signaling pathways involved in cell survival and proliferation. In particular, we find that the extracellular signal-regulated kinase 2 (ERK2; also known as mitogen-activated protein kinase 1 (MAPK1)) protein could mediate activation of 23 out of 29 (79%) of these upregulated pathways and thus may be regarded as the key player in establishing the t(8;21)-positive leukemic cells resistant to AE suppression.

Cagnetta A, Adamia S, Acharya C, et al.
Role of genotype-based approach in the clinical management of adult acute myeloid leukemia with normal cytogenetics.
Leuk Res. 2014; 38(6):649-59 [PubMed] Related Publications
Acute myeloid leukemia (AML) is the most common form of acute leukemia affecting adults. Although it is a complex disease driven by numerous genetic and epigenetic abnormalities, nearly 50% of patients exhibit a normal karyotype (CN-AML) with an intermediate cytogenetic risk. However, a widespread genomic analysis has recently shown the recurrence of genomic aberrations in this category (mutations of FLT3, CEBPA, NPM1, RUNX1, TET2, IDH1/2, DNMT3A, ASXL1, MLL and WT1) thus revealing its marked genomic heterogeneity. In this perspective, a global gene expression analysis of AML patients provides an independent prognostic marker to categorize each patient into clinic-pathologic subgroups based on its molecular genetic defects. Consistently such classification, taking into account the uniqueness of each AML patient, furnishes an individualized treatment approach leading a step closer to personalized medicine. Overall the genome-wide analysis of AML patients, by providing novel insights into biology of this tumor, furnishes accurate prognostic markers as well as useful tools for selecting the most appropriate treatment option. Moreover it provides novel therapeutic targets useful to enhance efficacy of the current anti-AML therapeutics. Here we describe the prognostic relevance of such new genetic data and discuss how this approach can be used to improve survival and treatment of AML patients.

Gu X, Hu Z, Ebrahem Q, et al.
Runx1 regulation of Pu.1 corepressor/coactivator exchange identifies specific molecular targets for leukemia differentiation therapy.
J Biol Chem. 2014; 289(21):14881-95 [PubMed] Article available free on PMC after 23/05/2015 Related Publications
Gene activation requires cooperative assembly of multiprotein transcription factor-coregulator complexes. Disruption to cooperative assemblage could underlie repression of tumor suppressor genes in leukemia cells. Mechanisms of cooperation and its disruption were therefore examined for PU.1 and RUNX1, transcription factors that cooperate to activate hematopoietic differentiation genes. PU.1 is highly expressed in leukemia cells, whereas RUNX1 is frequently inactivated by mutation or translocation. Thus, coregulator interactions of Pu.1 were examined by immunoprecipitation coupled with tandem mass spectrometry/Western blot in wild-type and Runx1-deficient hematopoietic cells. In wild-type cells, the NuAT and Baf families of coactivators coimmunoprecipitated with Pu.1. Runx1 deficiency produced a striking switch to Pu.1 interaction with the Dnmt1, Sin3A, Nurd, CoRest, and B-Wich corepressor families. Corepressors of the Polycomb family, which are frequently inactivated by mutation or deletion in myeloid leukemia, did not interact with Pu.1. The most significant gene ontology association of Runx1-Pu.1 co-bound genes was with macrophages, therefore, functional consequences of altered corepressor/coactivator exchange were examined at Mcsfr, a key macrophage differentiation gene. In chromatin immunoprecipitation analyses, high level Pu.1 binding to the Mcsfr promoter was not decreased by Runx1 deficiency. However, the Pu.1-driven shift from histone repression to activation marks at this locus, and terminal macrophage differentiation, were substantially diminished. DNMT1 inhibition, but not Polycomb inhibition, in RUNX1-translocated leukemia cells induced terminal differentiation. Thus, RUNX1 and PU.1 cooperate to exchange corepressors for coactivators, and the specific corepressors recruited to PU.1 as a consequence of RUNX1 deficiency could be rational targets for leukemia differentiation therapy.

Renneville A, Abdelali RB, Chevret S, et al.
Clinical impact of gene mutations and lesions detected by SNP-array karyotyping in acute myeloid leukemia patients in the context of gemtuzumab ozogamicin treatment: results of the ALFA-0701 trial.
Oncotarget. 2014; 5(4):916-32 [PubMed] Article available free on PMC after 23/05/2015 Related Publications
We recently showed that the addition of fractionated doses of gemtuzumab ozogamicin (GO) to standard chemotherapy improves clinical outcome of acute myeloid leukemia (AML) patients. In the present study, we performed mutational analysis of 11 genes (FLT3, NPM1, CEBPA, MLL, WT1, IDH1/2, RUNX1, ASXL1, TET2, DNMT3A), EVI1 overexpression screening, and 6.0 single-nucleotide polymorphism array (SNP-A) analysis in diagnostic samples of the 278 AML patients enrolled in the ALFA-0701 trial. In cytogenetically normal (CN) AML (n=146), 38% of the patients had at least 1 SNP-A lesion and 89% of the patients had at least 1 molecular alteration. In multivariate analysis, the independent predictors of higher cumulative incidence of relapse were unfavorable karyotype (P = 0.013) and randomization in the control arm (P = 0.007) in the whole cohort, and MLL partial tandem duplications (P = 0.014) and DNMT3A mutations (P = 0.010) in CN-AML. The independent predictors of shorter overall survival (OS) were unfavorable karyotype (P <0.001) and SNP-A lesion(s) (P = 0.001) in the whole cohort, and SNP-A lesion(s) (P = 0.006), DNMT3A mutations (P = 0.042) and randomization in the control arm (P = 0.043) in CN-AML. Interestingly, CN-AML patients benefited preferentially more from GO treatment as compared to AML patients with abnormal cytogenetics (hazard ratio for death, 0.52 versus 1.14; test for interaction, P = 0.04). Although the interaction test was not statistically significant, the OS benefit associated with GO treatment appeared also more pronounced in FLT3 internal tandem duplication positive than in negative patients.

Ommen HB, Hokland P, Haferlach T, et al.
Relapse kinetics in acute myeloid leukaemias with MLL translocations or partial tandem duplications within the MLL gene.
Br J Haematol. 2014; 165(5):618-28 [PubMed] Related Publications
Correct action upon re-emergence of minimal residual disease in acute myeloid leukaemia (AML) patients has not yet been established. The applicability of demethylating agents and use of allogeneic stem cell transplantation will be dependent on pre-relapse AML growth rates. We here delineate molecular growth kinetics of AML harbouring MLL partial tandem duplication (MLL-PTD; 37 cases) compared to those harbouring MLL translocations (43 cases). The kinetics of MLL-PTD relapses was both significantly slower than those of MLL translocation positive ones (median doubling time: MLL-PTD: 24 d, MLL-translocations: 12 d, P = 0·015, Wilcoxon rank sum test), and displayed greater variation depending on additional mutations. Thus, MLL-PTD+ cases with additional RUNX1 mutations or FLT3-internal tandem duplication relapsed significantly faster than cases without one of those two mutations (Wilcoxon rank sum test, P = 0·042). As rapid relapses occurred in all MLL subgroups, frequent sampling are necessary to obtain acceptable relapse detection rates and times from molecular relapse to haematological relapse (blood sampling every second month: MLL-PTD: 75%/50 d; MLL translocations: 85%/25 d). In conclusion, in this cohort relapse kinetics is heavily dependent on AML subtype as well as additional genetic aberrations, with possibly great consequences for the rational choice of pre-emptive therapies.

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.

Andrieu V, Radford-Weiss I, Troussard X, et al.
Molecular detection of t(8;21)/AML1-ETO in AML M1/M2: correlation with cytogenetics, morphology and immunophenotype.
Br J Haematol. 1996; 92(4):855-65 [PubMed] Related Publications
The t(8;21) identifies a subgroup of acute myeloid leukaemia (AML) with a relatively good prognosis which may merit different treatment. It is associated predominantly, but not exclusively, with AML M2, and corresponds to rearrangements involving the AML1 and ETO genes. AML1-ETO positive, t(8;21) negative cases are well recognized but their incidence is unknown. In order to determine optimal prospective AML1-ETO RT-PCR screening strategies, we analysed 64 unselected AML M1 and M2 cases and correlated the results with other biological parameters. Molecular screening increased the overall detection rate from 8% to 14%. AML1-ETO was found in 3% (1/32) of AML M1 and 25% (8/32) of M2, including three patients without a classic (8;21) but with chromosome 8 abnormalities. It was more common in younger patients. Correlation with morphology enabled development of a scoring system which detected all nine AML1-ETO-positive cases with a false positive rate of 7% (4/55). Although certain AML1-ETO-positive cases demonstrated characteristic immunological features (CD19 and CD34 expression, CD33 negativity), each of these markers was insufficiently specific to permit prediction in an individual case. We conclude that initial routine prospective molecular screening for AML1-ETO in all AMLs, combined with standardized morphological and immunological analysis, is desirable in order to produce improved prognostic stratification and to determine whether screening can ultimately be restricted to appropriate subgroups.

Rubin CM, Larson RA, Anastasi J, et al.
t(3;21)(q26;q22): a recurring chromosomal abnormality in therapy-related myelodysplastic syndrome and acute myeloid leukemia.
Blood. 1990; 76(12):2594-8 [PubMed] Related Publications
We have identified an identical reciprocal translocation between the long arms of chromosomes 3 and 21 with breakpoints at bands 3q26 and 21q22, [t(3;21)(q26;q22)], in the malignant cells from five adult patients with therapy-related myelodysplastic syndrome (t-MDS) or acute myeloid leukemia (t-AML). Primary diagnoses were Hodgkin's disease in two patients and ovarian carcinoma, breast cancer, and polycythemia vera in one patient each. Patients had been treated with chemotherapy including an alkylating agent for their primary disease 1 to 18 years before the development of t-MDS or t-AML. We have not observed the t(3;21) in over 1,500 patients with a myelodysplastic syndrome or acute myeloid leukemia arising de novo or in over 1,000 patients with lymphoid malignancies. We have previously reported that the t(3;21) occurs in Philadelphia chromosome-positive chronic myelogenous leukemia (CML). Thus, the t(3;21) appears to be limited to t-MDS/t-AML and CML, both of which represent malignant disorders of an early hematopoietic precursor cell. These results provide a new focus for the study of therapy-related leukemia at the molecular level.

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