The DNA methylome of pediatric acute lymphoblastic leukemia.
Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy, with high hyperdiploidy [51-67 chromosomes] and the t(12;21)(p13;q22) [ETV6/RUNX1 fusion] representing the most frequent abnormalities. Although these arise in utero, there is long latency before overt ALL, showing that additional changes are needed. Gene dysregulation through hypermethylation may be such an event; however, this has not previously been investigated in a detailed fashion. We performed genome-wide methylation profiling using bacterial artificial chromosome arrays and promoter-specific analyses of high hyperdiploid and ETV6/RUNX1-positive ALLs. In addition, global gene expression analyses were performed to identify associated expression patterns. Unsupervised cluster and principal component analyses of the chromosome-wide methylome profiles could successfully subgroup the two genetic ALL types. Analysis of all currently known promoter-specific CpG islands demonstrated that several B-cell- and neoplasia-associated genes were hypermethylated and underexpressed, indicating that aberrant methylation plays a significant leukemogenic role. Interestingly, methylation hotspots were associated with chromosome bands predicted to harbor imprinted genes and the tri-/tetrasomic chromosomes in the high hyperdiploid ALLs were less methylated than their disomic counterparts. Decreased methylation of gained chromosomes is a previously unknown phenomenon that may have ramifications not only for the pathogenesis of high hyperdiploid ALL but also for other disorders with acquired or constitutional numerical chromosome anomalies.
Davidsson
Josef
J
Department of Clinical Genetics, Lund University Hospital, Lund University, SE-221 85 Lund, Sweden. josef.davidsson@med.lu.se
Lilljebjörn
Henrik
H
Andersson
Anna
A
Veerla
Srinivas
S
Heldrup
Jesper
J
Behrendtz
Mikael
M
Fioretos
Thoas
T
Johansson
Bertil
B
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics; D051017:Apoptosis Regulatory Proteins / Q000235:genetics; D051242:Caveolin 1 / Q000235:genetics; D002648:Child; D002874:Chromosome Mapping; D050676:Core Binding Factor Alpha 2 Subunit / Q000235:genetics; D018899:CpG Islands / Q000235:genetics*; D019175:DNA Methylation; D020869:Gene Expression Profiling; D015894:Genome, Human / Q000235:genetics; D055106:Genome-Wide Association Study; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics; D000090243:Nucleophosmin; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics; D017422:Sequence Analysis, DNA / Q000379:methods; D013869:Thiolester Hydrolases; D025521:Tumor Suppressor Proteins / Q000235:genetics; D051025:bcl-Associated Death Protein / Q000235:genetics; D000097764:ETS Translocation Variant 6 Protein
D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; D051242:Caveolin 1; D050676:Core Binding Factor Alpha 2 Subunit; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D000090243:Nucleophosmin; D015514:Oncogene Proteins, Fusion; D011518:Proto-Oncogene Proteins; D013869:Thiolester Hydrolases; D025521:Tumor Suppressor Proteins; D051025:bcl-Associated Death Protein; C494819:BAD protein, human; C438378:BBC3 protein, human; C495540:CAV1 protein, human; C505360:CAVIN3 protein, human; C096151:CDK2AP1 protein, human; C102421:TEL-AML1 fusion protein; D000097764:ETS Translocation Variant 6 Protein; C437985:THEM4 protein, human