Gene Summary

Gene:AFF1; AF4/FMR2 family member 1
Aliases: AF4, PBM1, MLLT2
Summary:This gene encodes a member of the AF4/ lymphoid nuclear protein related to the Fragile X E syndrome (FRAXE) family of proteins, which have been implicated in human childhood lymphoblastic leukemia, fragile chromosome X intellectual disability, and ataxia. It is the prevalent mixed-lineage leukemia fusion gene associated with spontaneous acute lymphoblastic leukemia. Members of this family have three conserved domains: an N-terminal homology domain, an AF4/ lymphoid nuclear protein domain, and a C-terminal homology domain. The protein functions as a regulator of RNA polymerase II-mediated transcription through elongation and chromatin remodeling functions. Through RNA interference screens, this gene has been shown to promote the expression of CD133, a plasma membrane glycoprotein required for leukemia cell survival. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jul 2017]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:AF4/FMR2 family member 1
Source:NCBIAccessed: 01 September, 2019


What does this gene/protein do?
Show (5)

Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 01 September 2019 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.

  • Base Sequence
  • Childhood Cancer
  • Adolescents
  • Acute Lymphocytic Leukaemia
  • MLL
  • Sequence Homology
  • KMT2A
  • Leukaemia
  • Retinoic Acid
  • Precursor B-Cell Lymphoblastic Leukemia-Lymphoma
  • Promoter Regions
  • Twins, Dizygotic
  • Histone-Lysine N-Methyltransferase
  • Homologous Transplantat
  • Chromosome Aberrations
  • FISH
  • Polymerase Chain Reaction
  • Chromosome 11
  • Gene Rearrangement
  • Vidarabine
  • Neoplasm Proteins
  • Zinc Fingers
  • Oncogene Fusion Proteins
  • Nuclear Proteins
  • Cancer DNA
  • Transcriptional Activation
  • Validation Studies as Topic
  • AFF1
  • Amino Acid Sequence
  • DNA-Binding Proteins
  • Acute Myeloid Leukaemia
  • Infant
  • Transplantation, Haploidentical
  • Transcription Factors
  • Newborns
  • Molecular Sequence Data
  • DNA Sequence Analysis
  • Transcription
  • Messenger RNA
  • Chromosome 4
  • Proto-Oncogenes
Tag cloud generated 01 September, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (2)

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(4;11)(q21;q23) in Infant Leukaemia
Acute Lymphocytic Leukaemia (ALL)t(4;11)(q21;q23) MLL-AFF1 in adult acute lymphoblastic leukemia

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

Latest Publications: AFF1 (cancer-related)

Singh M, Bhatia P, Shandilya JK, et al.
Low Expression of Leucocyte Associated Immunoglobulin Like Receptor-1 (LAIR-1/CD305) in a Cohort of Pediatric Acute Lymphoblastic Leukemia Cases
Asian Pac J Cancer Prev. 2018; 19(11):3131-3135 [PubMed] Free Access to Full Article Related Publications
Background: Immunophenotypic markers can play significant role in prognostic assessment for different cancers and leukocyte-associated Ig-like receptor (LAIR-1) is a recently identified inhibitory immuno-receptor. Methods: We measured LAIR-1 expression in paediatric ALL patients (n-42) and appropriate controls by flow cytometry. Median fluorescence intensities (MFIs) were calculated and correlated with demographic and clinical variables and early treatment outcome parameters. Results: The ALL cohort had an age range of 1 - 11 y and a M:F ratio of 2.5:1. 64% had WBC counts <50 x 109/L and 15 (36%) >50 x 109/L, 52% being standard risk and 48% high risk. There were 6 cases of T-ALL and 36 of B-ALL. AML1-TEL, E2A-PBX, BCR-ABL and MLL-AF4 transcripts were noted in 3, 6, 2 and 1 patient, respectively. Day 8 ABC was <1,000 in 31 and >1,000 in 8 cases, while 30 had low and 7 high MRD (both >0.01) at day 35 of treatment. The median MFI for LAIR-1 expression in control cases was 8.2 (range 7.76-11.69) and in ALL cases 4.02 (range 0.56 to 11.87), with 74% (n-31) of ALL cases showing reduced LAIR-1 expression. However, no significant correlations were found between standard ALL risk factors and LAIR-1 expression. Out of 42 patients, 4 died during induction treatment and one exited therapy, 60% (n-3/5) of these featuring low expression of LAIR-1. Also ALL patients with low LAIR-1 expression had t (12;21), t (1;19) and t (4;11) translocations in 2, 4 and 1 samples, respectively, but none had t (9;22). Of those with high LAIR-1 expression, 2 had t (9;22) (MFIs-14.43 and 11.87). Conclusions: This pilot study of LAIR-1expression in ALL suggests low expression of the inhibitory molecule in leukemic cells. However, the findings need to be confirmed with larger cohort, along with studies focusing on pathophysiological roles in leukemic clone survival and escape from the immune system.

Urtishak KA, Wang LS, Culjkovic-Kraljacic B, et al.
Targeting EIF4E signaling with ribavirin in infant acute lymphoblastic leukemia.
Oncogene. 2019; 38(13):2241-2262 [PubMed] Free Access to Full Article Related Publications
The poor outcomes in infant acute lymphoblastic leukemia (ALL) necessitate new treatments. Here we discover that EIF4E protein is elevated in most cases of infant ALL and test EIF4E targeting by the repurposed antiviral agent ribavirin, which has anticancer properties through EIF4E inhibition, as a potential treatment. We find that ribavirin treatment of actively dividing infant ALL cells on bone marrow stromal cells (BMSCs) at clinically achievable concentrations causes robust proliferation inhibition in proportion with EIF4E expression. Further, we find that ribavirin treatment of KMT2A-rearranged (KMT2A-R) infant ALL cells and the KMT2A-AFF1 cell line RS4:11 inhibits EIF4E, leading to decreases in oncogenic EIF4E-regulated cell growth and survival proteins. In ribavirin-sensitive KMT2A-R infant ALL cells and RS4:11 cells, EIF4E-regulated proteins with reduced levels of expression following ribavirin treatment include MYC, MCL1, NBN, BCL2 and BIRC5. Ribavirin-treated RS4:11 cells exhibit impaired EIF4E-dependent nuclear to cytoplasmic export and/or translation of the corresponding mRNAs, as well as reduced phosphorylation of the p-AKT1, p-EIF4EBP1, p-RPS6 and p-EIF4E signaling proteins. This leads to an S-phase cell cycle arrest in RS4:11 cells corresponding to the decreased proliferation. Ribavirin causes nuclear EIF4E to re-localize to the cytoplasm in KMT2A-AFF1 infant ALL and RS4:11 cells, providing further evidence for EIF4E inhibition. Ribavirin slows increases in peripheral blasts in KMT2A-R infant ALL xenograft-bearing mice. Ribavirin cooperates with chemotherapy, particularly L-asparaginase, in reducing live KMT2A-AFF1 infant ALL cells in BMSC co-cultures. This work establishes that EIF4E is broadly elevated across infant ALL and that clinically relevant ribavirin exposures have preclinical activity and effectively inhibit EIF4E in KMT2A-R cases, suggesting promise in EIF4E targeting using ribavirin as a means of treatment.

Shi Y, Zhao Y, Zhang Y, et al.
AFF3 upregulation mediates tamoxifen resistance in breast cancers.
J Exp Clin Cancer Res. 2018; 37(1):254 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Although tamoxifen is a highly effective drug for treating estrogen receptor-positive (ER
METHODS: We investigated AFF3 expression in breast cancer cells and in clinical breast cancer specimens with western blot and Real-time PCR. We also examined the effects of AFF3 knockdown and overexpression on breast cancer cells using luciferase, tetrazolium, colony formation, and anchorage-independent growth assays in vitro and with nude mouse xenografting in vivo.
RESULTS: AFF3 was overexpressed in tamoxifen-resistant tumors. AFF3 overexpression in breast cancer cells resulted in tamoxifen resistance, whereas RNA interference-mediated gene knockdown reversed this phenotype. Furthermore, AFF3 upregulation led to estrogen-independent growth in the xenograft assays. Mechanistic investigations revealed that AFF3 overexpression activated the ER signaling pathway and transcriptionally upregulated a subset of ER-regulated genes. Clinical analysis showed that increased AFF3 expression in ER
CONCLUSIONS: These studies establish AFF3 as a key mediator of estrogen-independent growth and tamoxifen resistance and as a potential novel diagnostic and therapeutic target.

Chu SH, Song EJ, Chabon JR, et al.
Inhibition of MEK and ATR is effective in a B-cell acute lymphoblastic leukemia model driven by
Blood Adv. 2018; 2(19):2478-2490 [PubMed] Free Access to Full Article Related Publications
Infant B-cell acute lymphoblastic leukemias (B-ALLs) that harbor

Peterson JF, Baughn LB, Pearce KE, et al.
KMT2A (MLL) rearrangements observed in pediatric/young adult T-lymphoblastic leukemia/lymphoma: A 10-year review from a single cytogenetic laboratory.
Genes Chromosomes Cancer. 2018; 57(11):541-546 [PubMed] Related Publications
T-lymphoblastic leukemia/lymphoma (T-ALL/LBL) accounts for approximately 15% of pediatric and 25% of adult ALL. While the underlying frequency of KMT2A (MLL) gene rearrangements has been identified in approximately 4-8% of T-ALL/LBL cases, a paucity of literature is available to characterize further the KMT2A rearrangements in pediatric/young adult T-ALL/LBL. A 10-year retrospective review was performed to identify KMT2A rearrangements in specimens sent for T-ALL/LBL fluorescence in situ hybridization studies in patients under the age of 30 years. Of 806 T-ALL/LBL FISH studies performed on unique individuals, 27 (3.3%) harbored KMT2A rearrangements. Nineteen patients were male and eight were female (M:F ratio, 2.4:1) with ages ranging from 1 to 20 years (mean 12, median 12). Of the 27 cases, nine (33%) had KMT2A/MLLT1 fusions, eight (30%) had KMT2A/AFDN fusions, two (7%) had KMT2A/ELL fusions, and one (4%) had a KMT2A/MLLT10 fusion. In addition, five (19%) had KMT2A rearrangements with unidentified gene fusion partners and two (7%) had 3'KMT2A deletions. Our results indicate that MLLT1 and AFDN account for the majority (63%) of KMT2A gene partners in pediatric/young adult T-ALL/LBL, while no KMT2A/AFF1 or KMT2A/MLLT3 fusions were observed despite their common identification in B-ALL and acute myeloid leukemia, respectively. In addition to diagnostic and prognostic value, detecting specific KMT2A fusions may also be of clinical importance in the era of targeted therapies.

Chen X, Wang F, Zhang Y, et al.
Retrospective analysis of 36 fusion genes in 2479 Chinese patients of de novo acute lymphoblastic leukemia.
Leuk Res. 2018; 72:99-104 [PubMed] Related Publications
Fusion genes are major molecular biological abnormalities in hematological malignancies. To depict the common recurrent gene-fusion landscape in acute lymphoblastic leukemia (ALL), 36 recurrent fusion genes in hematologic malignancies were assessed using multiplex-nested RT-PCR in 2479 patients with de novo ALL. 17 kinds of distinct fusion genes were detected in 712 (28.72%) cases. Co-occurrence of different fusion genes was observed in 6 (0.24%) patients. Incidence of fusion genes in B-ALL was significantly higher than in T-ALL (31.40% vs. 14.50%, P < 0.001). Pediatric ALL had higher prevalence of ETV6-RUNX1, TCF3-PBX1, and STIL-TAL1, while BCR-ABL1 and SET-NUP214 were more common in adult ALL. BCR-ABL1, TCF3-PBX1, KMT2A-AFF1 and ETV6-RUNX1 were more frequent in B-ALL. On the contrary, KMT2A-MLLT4, SET-NUP214 and STIL-TAL1 were of higher incidence in T-ALL. In comparison with Western cohorts, the incidence of BCR-ABL1 (5.94%) was much higher in our series, while the occurrence of ETV6-RUNX1 (13.19%) was significantly lower in pediatric B-ALL patients in our study than in Western reports. This study provides a genetic landscape of common fusion genes in ALL patients and may serve as a foundation for further improvement of a fusion gene screening panel for clinical applications.

Roberts I, Fordham NJ, Rao A, Bain BJ
Neonatal leukaemia.
Br J Haematol. 2018; 182(2):170-184 [PubMed] Related Publications
Neonatal leukaemia is defined as occurring within the first 28 days of life and most, if not all, cases are congenital. With the exception of Down syndrome-associated transient abnormal myelopoiesis, which is not considered here, neonatal leukaemias are rare. In two-thirds of patients the disease manifests as an acute myeloid leukaemia, frequently with monocytic/monoblastic characteristics. Most other cases are acute lymphoblastic leukaemia, particularly B lineage, but some are mixed phenotype or blastic plasmacytoid dendritic cell neoplasms. The most frequently observed cytogenetic/molecular abnormality is t(4;11)(q21.3;q23.3)/KMT2A-AFF1 followed by t(1;22)(p13.3;q13.1)/RBM15-MKL1 and t(8;16)(p11.2;p13.3)/KAT6A-CREBBP. Common clinical features include prominent hepatosplenomegaly and a high incidence of skin involvement, sometimes in the absence of bone marrow disease. A distinctive feature is the occurrence of spontaneous remission in some cases, particularly in association with t(8;16). In this review, we summarise current knowledge of the clinical, cytogenetic and molecular features of neonatal leukaemia and discuss clinical management of these cases.

Liu G, Lu X, Kim YM, et al.
Simultaneous involvement of 11q23 translocation resulting in chimeric MLL-AFF1 and a second translocation [t (9;21) (p13; p11.2)] in an infant acute lymphoblastic leukemia patient at relapse: A case report.
Medicine (Baltimore). 2018; 97(21):e10874 [PubMed] Free Access to Full Article Related Publications
RATIONALE: Three-way translocations occasionally occur in MLL-AFF1 fusion and other fusion gene. However, the complex chromosomal rearrangements in the study were the first report.
PATIENT CONCERNS: We present novel cryptic and complex chromosomal rearrangements [der (21) t (9; 21) (p13; p11.2)] in an infant patient with relapsed acute lymphoblastic leukemia (ALL).
DIAGNOSES: The diagnosis was based on morphologic, cytochemical, and immunophenotypic criteria proposed by the French-American-British Committee, and karyotype, fluorescence in situ hybridization, array comparative genomic hybridization.
INTERVENTIONS: The patient was given chemotherapy with standard protocol for ALL.
OUTCOMES: The patient had unfavorable prognostic outcome based on the cytogenetic and molecular cytogenetic markers. After short remission, the patient relapsed.
LESSONS: MLL-AFF1, resulting from t(4;11)(q21;q23), is regarded as the hallmark of infant t(4;11) pre-B/mixed B-ALL. It is associated with a dismal prognosis and the multiple-way translocation involving chromosomes 4, 11 and 11 may function as an enhancer.

Greaves M
A causal mechanism for childhood acute lymphoblastic leukaemia.
Nat Rev Cancer. 2018; 18(8):471-484 [PubMed] Related Publications
In this Review, I present evidence supporting a multifactorial causation of childhood acute lymphoblastic leukaemia (ALL), a major subtype of paediatric cancer. ALL evolves in two discrete steps. First, in utero initiation by fusion gene formation or hyperdiploidy generates a covert, pre-leukaemic clone. Second, in a small fraction of these cases, the postnatal acquisition of secondary genetic changes (primarily V(D)J recombination-activating protein (RAG) and activation-induced cytidine deaminase (AID)-driven copy number alterations in the case of ETS translocation variant 6 (ETV6)-runt-related transcription factor 1 (RUNX1)

Deng P, Wang J, Zhang X, et al.
AFF4 promotes tumorigenesis and tumor-initiation capacity of head and neck squamous cell carcinoma cells by regulating SOX2.
Carcinogenesis. 2018; 39(7):937-947 [PubMed] Free Access to Full Article Related Publications
Super elongation complex (SEC) controls gene transcription by releasing Pol II from pausing. Previous studies have shown that dysfunction of SEC was associated with multiple human cancers, such as leukemia and breast cancer. However, the role of SEC in head and neck squamous cell carcinoma (HNSCC) development remains largely unknown. In this study, we found expression of AF4/FMR2 family member 4 (AFF4), the core component of SEC, was upregulated dramatically in HNSCC cell lines and tumor tissues. By using siRNA-mediated depletion and overexpression of AFF4, we demonstrated AFF4 promoted proliferation, migration and invasion of HNSCC cells. Moreover, we found AFF4 enhanced the aldehyde dehydrogenase (ALDH) activity and sphere formatting activity and was required for the tumor-initiation capacity of stem-like cells in HNSCC cell lines. Mechanistically, we found the role of AFF4 in regulation of HNSCC cell behaviors was mainly mediated by sex-determining region Y box2 (SOX2), a critical regulator involved in development of several human cancers. SOX2 expression changed in parallel with AFF4 expression in response to depletion and overexpression of AFF4, respectively. More importantly, overexpression of SOX2 rescued the inhibited proliferation, migration, invasion and ALDH activity induced by knockdown of AFF4 in HNSCC cells, at least in part. Collectively, our findings indicate AFF4 may serve as a biomarker and a potential target of therapies for patients with HNSCC.

Singh M, Bhatia P, Trehan A, et al.
High frequency of intermediate and poor risk copy number abnormalities in pediatric cohort of B-ALL correlate with high MRD post induction.
Leuk Res. 2018; 66:79-84 [PubMed] Related Publications
Copy number abnormalities (CNAs) and recurrent fusion transcripts are important genetic events which define and prognosticate B-Cell Acute Lymphoblastic Leukemia (B-ALL). We evaluated CNAs and fusion transcripts in 67 pediatric B-ALL cases and correlated the data with standard risk factors and early treatment outcome parameters. Common fusion transcripts ETV6-RUNX1, E2A-PBX, BCR-ABL1 and MLL-AF4 were examined by RT-PCR and noted in 15%, 15%, 13% and 1.4% of all cases respectively. CNAs in IKZF1, PAX5, EBF1, BTG1, RB1, CDKN2A/B and genes from PAR1 region viz., CSF2RA, IL3RA,P2RY8, SHOX region and CRLF2 were analyzed by multiplex ligation dependent probe amplification assay and were detected in 70% (47/67) of cases, with predominantly deletions in CDKN2A/B (36%), PAX5 (18%) and IKZF1 (16%). A statistically significant association of intermediate/poor risk CNAs was noted with high WBC count (p = 0.001), NCI group (p = 0.02) and minimal residual disease at Day35 (p < 0.0001). IKZF1 and CDKN2A/B deletion revealed poor EFS of 56% at 24 months as compared to EFS of 80% in rest of the cases (p = 0.05) suggesting their potential role in early risk stratification.

Tan YT, Ye L, Xie F, et al.
Respecifying human iPSC-derived blood cells into highly engraftable hematopoietic stem and progenitor cells with a single factor.
Proc Natl Acad Sci U S A. 2018; 115(9):2180-2185 [PubMed] Free Access to Full Article Related Publications
Derivation of human hematopoietic stem cells (HSCs) from induced pluripotent stem cells (iPSCs) offers considerable promise for cell therapy, disease modeling, and drug screening. However, efficient derivation of functional iPSC-derived HSCs with in vivo engraftability and multilineage potential remains challenging. Here, we demonstrate a tractable approach for respecifying iPSC-derived blood cells into highly engraftable hematopoietic stem and progenitor cells (HSPCs) through transient expression of a single transcription factor,

Afrin S, Zhang CRC, Meyer C, et al.
Targeted Next-Generation Sequencing for Detecting
Mol Cancer Res. 2018; 16(2):279-285 [PubMed] Related Publications
Mixed lineage leukemia (

Malouf C, Ottersbach K
Molecular processes involved in B cell acute lymphoblastic leukaemia.
Cell Mol Life Sci. 2018; 75(3):417-446 [PubMed] Free Access to Full Article Related Publications
B cell leukaemia is one of the most frequent malignancies in the paediatric population, but also affects a significant proportion of adults in developed countries. The majority of infant and paediatric cases initiate the process of leukaemogenesis during foetal development (in utero) through the formation of a chromosomal translocation or the acquisition/deletion of genetic material (hyperdiploidy or hypodiploidy, respectively). This first genetic insult is the major determinant for the prognosis and therapeutic outcome of patients. B cell leukaemia in adults displays similar molecular features as its paediatric counterpart. However, since this disease is highly represented in the infant and paediatric population, this review will focus on this demographic group and summarise the biological, clinical and epidemiological knowledge on B cell acute lymphoblastic leukaemia of four well characterised subtypes: t(4;11) MLL-AF4, t(12;21) ETV6-RUNX1, t(1;19) E2A-PBX1 and t(9;22) BCR-ABL1.

Tamai H, Yamaguchi H, Miyake K, et al.
Amlexanox Downregulates S100A6 to Sensitize
Cancer Res. 2017; 77(16):4426-4433 [PubMed] Related Publications
Acute lymphoblastic leukemias (ALL) positive for

Lin S, Luo RT, Shrestha M, et al.
The full transforming capacity of MLL-Af4 is interlinked with lymphoid lineage commitment.
Blood. 2017; 130(7):903-907 [PubMed] Free Access to Full Article Related Publications
Chromosome rearrangements involving the mixed-lineage leukemia gene (MLL) create MLL-fusion proteins, which could drive both acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). The lineage decision of MLL-fusion leukemia is influenced by the fusion partner and microenvironment. To investigate the interplay of fusion proteins and microenvironment in lineage choice, we transplanted human hematopoietic stem and progenitor cells (HSPCs) expressing MLL-AF9 or MLL-Af4 into immunodeficient NSGS mice, which strongly promote myeloid development. Cells expressing MLL-AF9 efficiently developed AML in NSGS mice. In contrast, MLL-Af4 cells, which were fully oncogenic under lymphoid conditions present in NSG mice, displayed compromised transformation capacity in a myeloid microenvironment. MLL-Af4 activated a self-renewal program in a lineage-dependent manner, showing the leukemogenic activity of MLL-Af4 was interlinked with lymphoid lineage commitment. The C-terminal homology domain (CHD) of Af4 was sufficient to confer this linkage. Although the MLL-CHD fusion protein failed to immortalize HSPCs in myeloid conditions in vitro, it could successfully induce ALL in NSG mice. Our data suggest that defective self-renewal ability and leukemogenesis of MLL-Af4 myeloid cells could contribute to the strong B-cell ALL association of MLL-AF4 leukemia observed in the clinic.

Navarrete-Meneses MP, Salas-Labadía C, Sanabrais-Jiménez M, et al.
"Exposure to the insecticides permethrin and malathion induces leukemia and lymphoma-associated gene aberrations in vitro".
Toxicol In Vitro. 2017; 44:17-26 [PubMed] Related Publications
Epidemiological studies have associated the exposure to permethrin and malathion with increased risk of leukemia and lymphoma. The aim of this study was to evaluate whether in vitro exposure to permethrin and malathion induces aberrations in genes involved in the etiology of these hematological malignancies. Genetic abnormalities in the IGH, KMT2A (MLL), ETV6 and RUNX1 genes, and aneuploidy induced by the in vitro exposure to permethrin and malathion (200μM, 24h), were analyzed by FISH in peripheral blood mononuclear cells (PBMCs). The gene fusions IGH-BCL2, KMT2A-AFF1 and ETV6-RUNX1 were further analyzed with nested RT-PCR in PBMCs, and in K562 cells exposed to acute and chronic treatments (0.1μM, 24h or every third day for two weeks) of insecticides. FISH analysis revealed that permethrin induces aneuploidy and structural alterations in IGH and KMT2A genes, and malathion induces breaks in KMT2A. RT-PCR detected ETV6-RUNX1 fusion in PBMCs acutely exposed to permethrin. Permethrin also induced ETV6-RUNX1 and IGH-BCL2 fusions in K562 cells, and malathion induced KMT2A-AFF1 and ETV6-RUNX1 fusions. Overall, we identified that both insecticides induce breaks and fusions in the studied genes, and permethrin induces aneuploidy. This study presents evidence of damage in cancer genes caused by these insecticides.

Rosales-Rodríguez B, Fernández-Ramírez F, Núñez-Enríquez JC, et al.
Copy Number Alterations Associated with Acute Lymphoblastic Leukemia in Mexican Children. A report from The Mexican Inter-Institutional Group for the identification of the causes of childhood leukemia.
Arch Med Res. 2016; 47(8):706-711 [PubMed] Related Publications
B-cell precursor acute lymphocytic leukemia (B-ALL) represents a worldwide public health issue. Particularly, Mexico is one of the countries with the highest incidence of ALL in children. Between the multiple factors involved in ALL etiology, genetic alterations are clearly one of the most relevant features. In this work, a group of 24 B-ALL patients, all negative for the four most frequent gene fusions (ETV6-RUNX1, BCR-ABL1, TCF3-PBX1 and MLL-AF4), were included in a high-resolution microarray analysis in order to evaluate genomic copy-number alterations (CNAs). The results of this preliminary report showed a broad genomic heterogeneity among the studied samples; 58% of the patients were hyperdiploid and 33% displayed a chromosome 9p deletion of variable length affecting genes CDKN2A/B, two patients displayed genomic instability with a high number of focal CNAs, three patients presented unique duplications affecting 2q, 12p and 1q, respectively, and one patient displayed no copy number imbalances. The copy-number profile of 44 genes previously related to B-ALL was heterogeneous as well. Overall results highlight the need for a detailed description of the genetic alterations in ALL cancer cells in order to understand the molecular pathogenesis of the disease and to identify any prognostic markers with clinical significance.

Kosik P, Skorvaga M, Durdik M, et al.
Low numbers of pre-leukemic fusion genes are frequently present in umbilical cord blood without affecting DNA damage response.
Oncotarget. 2017; 8(22):35824-35834 [PubMed] Free Access to Full Article Related Publications
Despite widely accepted notion that many childhood leukemias are likely developed from hematopoietic stem/progenitor cells (HSPC) with pre-leukemic fusion genes (PFG) formed in embryonic/fetal development, the data on PFG incidence in newborns are contradictive. To provide a better understanding of a prenatal origin of leukemia, umbilical cord blood from 500 newborns was screened for the presence of the most frequent PFG associated with pediatric B-cell acute lymphoblastic leukemia. This screening revealed relatively high incidence of ETV6-RUNX1, BCR-ABL1 (p190) and MLL-AF4 at very low frequencies, averaging ~14 copies per 100,000 cells. We assume that most of these PFG might originate relatively late in embryonic/fetal development and will be eliminated later during postnatal development. The obtained results suggested that higher PFG copy numbers originating in specific time windows of the hematopoietic stem cell hierarchy may define a better prognostic tool for the assessment of leukemogenic potential. We have observed no significant effect of low-copy PFG on radiation-induced DNA damage response, accumulation of endogenous DNA double-stranded breaks, and apoptosis in either lymphocytes or HSPC. Imaging flow cytometry showed lower level of γH2AX foci in HSPC in comparison to lymphocytes suggesting better protection of HSPC from DNA damage.

Bhandari P, Ahmad F, Das BR
Molecular profiling of gene copy number abnormalities in key regulatory genes in high-risk B-lineage acute lymphoblastic leukemia: frequency and their association with clinicopathological findings in Indian patients.
Med Oncol. 2017; 34(5):92 [PubMed] Related Publications
Genes related to key cellular pathways are frequently altered in B cell ALL and are associated with poor survival especially in high-risk (HR) subgroups. We examined gene copy number abnormalities (CNA) in 101 Indian HR B cell ALL patients and their correlation with clinicopathological features by multiplex ligation-dependent probe amplification. Overall, CNA were detected in 59 (59%) cases, with 26, 10 and 23% of cases harboring 1, 2 or +3 CNA. CNA were more prevalent in BCR-ABL1 (60%), pediatric (64%) and high WCC (WBC count) (63%) patients. Frequent genes deletions included CDNK2A/B (26%), IKZF1 (25%), PAX5 (14%), JAK2 (7%), BTG1 (6%), RB1 (5%), EBF1 (4%), ETV6 (4%), while PAR1 region genes were predominantly duplicated (20%). EBF1 deletions selectively associated with adults, IKZF1 deletions occurred frequently in high WCC and BCR-ABL1 cases, while PAR1 region gains significantly associated with MLL-AF4 cases. IKZF1 haploinsufficiency group was predominant, especially in adults (65%), high WCC (60%) patients and BCR-ABL1-negative (78%) patients. Most cases harbored multiple concurrent CNA, with IKZF1 concomitantly occurring with CDNK2A/B, PAX5 and BTG1, while JAK2 occurred with CDNK2A/B and PAX5. Mutually exclusive CNA included ETV6 and IKZF1/RB1, and EBF1 and JAK2. Our results corroborate with global reports, aggregating molecular markers in Indian HR B-ALL cases. Integration of CNA data from rapid methods like MLPA, onto background of existing gold-standard methods detecting significant chromosomal abnormalities, provides a comprehensive genetic profile in B-ALL.

Okuda H, Stanojevic B, Kanai A, et al.
Cooperative gene activation by AF4 and DOT1L drives MLL-rearranged leukemia.
J Clin Invest. 2017; 127(5):1918-1931 [PubMed] Free Access to Full Article Related Publications
The eleven-nineteen leukemia (ENL) protein family, composed of ENL and AF9, is a common component of 3 transcriptional modulators: AF4-ENL-P-TEFb complex (AEP), DOT1L-AF10-ENL complex (referred to as the DOT1L complex) and polycomb-repressive complex 1 (PRC1). Each complex associates with chromatin via distinct mechanisms, conferring different transcriptional properties including activation, maintenance, and repression. The mixed-lineage leukemia (MLL) gene often fuses with ENL and AF10 family genes in leukemia. However, the functional interrelationship among those 3 complexes in leukemic transformation remains largely elusive. Here, we have shown that MLL-ENL and MLL-AF10 constitutively activate transcription by aberrantly inducing both AEP-dependent transcriptional activation and DOT1L-dependent transcriptional maintenance, mostly in the absence of PRC1, to fully transform hematopoietic progenitors. These results reveal a cooperative transcriptional activation mechanism of AEP and DOT1L and suggest a molecular rationale for the simultaneous inhibition of the MLL fusion-AF4 complex and DOT1L for more effective treatment of MLL-rearranged leukemia.

Yoshimi A, Kato K, Hosaka S, et al.
Haploidentical peripheral blood stem cell transplantation without irradiation or busulfan after reduced-intensity conditioning for KMT2A(MLL)-rearranged infant B-cell precursor acute lymphoblastic leukemia: Report of two cases.
Pediatr Transplant. 2017; 21(4) [PubMed] Related Publications
We present two infants with KMT2A(MLL)-gene-R-associated BCP-ALL, who received HLA haploidentical PBSCT after RIC. The patients developed ALL at age 6 months and 3 months, respectively. Case 1 underwent PBSCT at the second CR with detectable KMT2A-AFF1(MLL-AF4) fusion gene transcript at 11 months of age, and Case 2 at the first CR without KMT2A-MLLT1(MLL-ENL) fusion gene transcript at 8 months of age. Both patients received G-CSF-mobilized unmanipulated peripheral blood mononuclear cells from their HLA haploidentical mothers after administration of FLU, MEL, and ATG. Tacrolimus, methotrexate, and mPSL were administered as prophylaxis against GVHD. Engraftment was rapidly obtained with complete chimerism in both patients. Acute adverse events included acute GVHD in Case 1 and bacterial sepsis in Case 2. At last clinical check at age 5 years and 4 years, respectively, both patients were recurrence-free and attained normal growth and development. We conclude that PBSCT from an HLA haploidentical mother with non-TBI and non-BU regimen seems feasible and efficacious, offering favorable life quality for infants.

Erb MA, Scott TG, Li BE, et al.
Transcription control by the ENL YEATS domain in acute leukaemia.
Nature. 2017; 543(7644):270-274 [PubMed] Free Access to Full Article Related Publications
Recurrent chromosomal translocations producing a chimaeric MLL oncogene give rise to a highly aggressive acute leukaemia associated with poor clinical outcome. The preferential involvement of chromatin-associated factors as MLL fusion partners belies a dependency on transcription control. Despite recent progress made in targeting chromatin regulators in cancer, available therapies for this well-characterized disease remain inadequate, prompting the need to identify new targets for therapeutic intervention. Here, using unbiased CRISPR-Cas9 technology to perform a genome-scale loss-of-function screen in an MLL-AF4-positive acute leukaemia cell line, we identify ENL as an unrecognized gene that is specifically required for proliferation in vitro and in vivo. To explain the mechanistic role of ENL in leukaemia pathogenesis and dynamic transcription control, a chemical genetic strategy was developed to achieve targeted protein degradation. Acute loss of ENL suppressed the initiation and elongation of RNA polymerase II at active genes genome-wide, with pronounced effects at genes featuring a disproportionate ENL load. Notably, an intact YEATS chromatin-reader domain was essential for ENL-dependent leukaemic growth. Overall, these findings identify a dependency factor in acute leukaemia and suggest a mechanistic rationale for disrupting the YEATS domain in disease.

Milne TA
Mouse models of MLL leukemia: recapitulating the human disease.
Blood. 2017; 129(16):2217-2223 [PubMed] Free Access to Full Article Related Publications
Chromosome translocations involving the mixed lineage leukemia (

Prange KHM, Mandoli A, Kuznetsova T, et al.
MLL-AF9 and MLL-AF4 oncofusion proteins bind a distinct enhancer repertoire and target the RUNX1 program in 11q23 acute myeloid leukemia.
Oncogene. 2017; 36(23):3346-3356 [PubMed] Free Access to Full Article Related Publications
In 11q23 leukemias, the N-terminal part of the mixed lineage leukemia (MLL) gene is fused to >60 different partner genes. In order to define a core set of MLL rearranged targets, we investigated the genome-wide binding of the MLL-AF9 and MLL-AF4 fusion proteins and associated epigenetic signatures in acute myeloid leukemia (AML) cell lines THP-1 and MV4-11. We uncovered both common as well as specific MLL-AF9 and MLL-AF4 target genes, which were all marked by H3K79me2, H3K27ac and H3K4me3. Apart from promoter binding, we also identified MLL-AF9 and MLL-AF4 binding at specific subsets of non-overlapping active distal regulatory elements. Despite this differential enhancer binding, MLL-AF9 and MLL-AF4 still direct a common gene program, which represents part of the RUNX1 gene program and constitutes of CD34

Fabiani E, Falconi G, Fianchi L, et al.
Clonal evolution in therapy-related neoplasms.
Oncotarget. 2017; 8(7):12031-12040 [PubMed] Free Access to Full Article Related Publications
Therapy-related myeloid neoplasms (t-MN) may occur as a late effect of cytotoxic therapy for a primary malignancy or autoimmune diseases in susceptible individuals. We studied the development of somatic mutations in t-MN, using a collection of follow-up samples from 14 patients with a primary hematologic malignancy, who developed a secondary leukemia (13 t-MN and 1 t-acute lymphoblastic leukemia), at a median latency of 73 months (range 18-108) from primary cancer diagnosis.Using Sanger and next generation sequencing (NGS) approaches we identified 8 mutations (IDH1 R132H, ASXL1 Y591*, ASXL1 S689*, ASXL1 R693*, SRSF2 P95H, SF3B1 K700E, SETBP1 G870R and TP53 Y220C) in seven of thirteen t-MN patients (54%), whereas the t-ALL patient had a t(4,11) translocation, resulting in the KMT2A/AFF1 fusion gene. These mutations were then tracked backwards in marrow samples preceding secondary leukemia occurrence, using pyrosequencing and a NGS protocol that allows the detection of low variant allele frequencies (≥0.1%).Somatic mutations were detectable in the BM harvested at the primary diagnosis, prior to any cytotoxic treatment in three patients, while they were not detectable and apparently acquired by the t-MN clone in five patients.These data show that clonal evolution in t-MN is heterogeneous, with some somatic mutations preceding cytotoxic treatment and possibly favoring leukemic development.

Kerry J, Godfrey L, Repapi E, et al.
MLL-AF4 Spreading Identifies Binding Sites that Are Distinct from Super-Enhancers and that Govern Sensitivity to DOT1L Inhibition in Leukemia.
Cell Rep. 2017; 18(2):482-495 [PubMed] Free Access to Full Article Related Publications
Understanding the underlying molecular mechanisms of defined cancers is crucial for effective personalized therapies. Translocations of the mixed-lineage leukemia (MLL) gene produce fusion proteins such as MLL-AF4 that disrupt epigenetic pathways and cause poor-prognosis leukemias. Here, we find that at a subset of gene targets, MLL-AF4 binding spreads into the gene body and is associated with the spreading of Menin binding, increased transcription, increased H3K79 methylation (H3K79me2/3), a disruption of normal H3K36me3 patterns, and unmethylated CpG regions in the gene body. Compared to other H3K79me2/3 marked genes, MLL-AF4 spreading gene expression is downregulated by inhibitors of the H3K79 methyltransferase DOT1L. This sensitivity mediates synergistic interactions with additional targeted drug treatments. Therefore, epigenetic spreading and enhanced susceptibility to epidrugs provides a potential marker for better understanding combination therapies in humans.

Yokoyama A
Transcriptional activation by MLL fusion proteins in leukemogenesis.
Exp Hematol. 2017; 46:21-30 [PubMed] Related Publications
Chromosomal translocations involving the mixed lineage leukemia (MLL) gene cause aggressive leukemia. Fusion proteins of MLL and a component of the AF4 family/ENL family/P-TEFb complex (AEP) are responsible for two-thirds of MLL-associated leukemia cases. MLL-AEP fusion proteins trigger aberrant self-renewal of hematopoietic progenitors by constitutively activating self-renewal-related genes. MLL-AEP fusion proteins activate transcription initiation by loading the TATA-binding protein (TBP) to the TATA element via selectivity factor 1. Although AEP retains transcription elongation and mediator recruiting activities, the rate-limiting step activated by MLL-AEP fusion proteins appears to be the TBP-loading step. This is contrary to prevailing views, in which the recruitment of transcription elongation activities are emphasized. Here, I review recent advances towards elucidating the mechanisms underlying gene activation by MLL-AEP fusion proteins in leukemogenesis.

Lin S, Luo RT, Ptasinska A, et al.
Instructive Role of MLL-Fusion Proteins Revealed by a Model of t(4;11) Pro-B Acute Lymphoblastic Leukemia.
Cancer Cell. 2016; 30(5):737-749 [PubMed] Related Publications
The t(4;11)(q21;q23) fuses mixed-lineage leukemia (MLL) to AF4, the most common MLL-fusion partner. Here we show that MLL fused to murine Af4, highly conserved with human AF4, produces high-titer retrovirus permitting efficient transduction of human CD34

Bergmann AK, Castellano G, Alten J, et al.
DNA methylation profiling of pediatric B-cell lymphoblastic leukemia with KMT2A rearrangement identifies hypomethylation at enhancer sites.
Pediatr Blood Cancer. 2017; 64(3) [PubMed] Related Publications
Deregulation of the epigenome is an important pathogenetic mechanism in acute lymphoblastic leukemia (ALL) with lysine (K)-specific methyltransferase 2A rearrangement (KMT2Ar). We performed array-based DNA methylation profiling of KMT2Ar ALL cells from 26 children in comparison to normal B-cell precursors. Significant changes in DNA methylation in KMT2Ar ALL were identified in 2,545 CpG loci, influenced by age and the translocation partners AFF1 and MLLT1. In KMT2Ar ALL, DNA methylation loss was enriched at enhancers and for certain transcription factor binding sites such as BCL11A, EBF, and MEF2A. In summary, DNA methylation changes in KMT2Ar ALL target enhancers, genes involved in leukemogenesis and normal hematopoiesis, as well as transcription factor networks.

Disclaimer: This site is for educational purposes only; it can not be used in diagnosis or treatment.

Cite this page: Cotterill SJ. MLLT2, Cancer Genetics Web: Accessed:

Creative Commons License
This page in Cancer Genetics Web by Simon Cotterill is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Note: content of abstracts copyright of respective publishers - seek permission where appropriate.

 [Home]    Page last revised: 01 September, 2019     Cancer Genetics Web, Established 1999