title: Hypermethylation of the alternative AWT1 promoter in hematological malignancies is a highly specific marker for acute myeloid leukemias despite high expression levels.
abstract: BACKGROUND
  Wilms tumor 1 (WT1) is over-expressed in numerous cancers with respect to normal cells, and has either a tumor suppressor or oncogenic role depending on cellular context. This gene is associated with numerous alternatively spliced transcripts, which initiate from two different unique first exons within the WT1 and the alternative (A)WT1 promoter intervals. Within the hematological system, WT1 expression is restricted to CD34+/CD38- cells and is undetectable after differentiation. Detectable expression of this gene is an excellent marker for minimal residual disease in acute myeloid leukemia (AML), but the underlying epigenetic alterations are unknown.
  
  
  METHODS
  To determine the changes in the underlying epigenetic landscape responsible for this expression, we characterized expression, DNA methylation and histone modification profiles in 28 hematological cancer cell lines and confirmed the methylation signature in 356 cytogenetically well-characterized primary hematological malignancies.
  
  
  RESULTS
  Despite high expression of WT1 and AWT1 transcripts in AML-derived cell lines, we observe robust hypermethylation of the AWT1 promoter and an epigenetic switch from a permissive to repressive chromatin structure between normal cells and AML cell lines. Subsequent methylation analysis in our primary leukemia and lymphoma cohort revealed that the epigenetic signature identified in cell lines is specific to myeloid-lineage malignancies, irrespective of underlying mutational status or translocation. In addition to being a highly specific marker for AML diagnosis (positive predictive value 100%; sensitivity 86.1%; negative predictive value 89.4%), we show that AWT1 hypermethylation also discriminates patients that relapse from those achieving complete remission after hematopoietic stem cell transplantation, with similar efficiency to WT1 expression profiling.
  
  
  CONCLUSIONS
  We describe a methylation signature of the AWT1 promoter CpG island that is a promising marker for classifying myeloid-derived leukemias. In addition AWT1 hypermethylation is ideally suited to monitor the recurrence of disease during remission in patients undergoing allogeneic stem cell transfer.
authors.forename: Amy
authors.initials: A
authors.lastname: Guillaumet-Adkins
authors.forename: Julia
authors.initials: J
authors.lastname: Richter
authors.forename: Maria D
authors.initials: MD
authors.lastname: Odero
authors.forename: Juan
authors.initials: J
authors.lastname: Sandoval
authors.forename: Xabi
authors.initials: X
authors.lastname: Agirre
authors.forename: Albert
authors.initials: A
authors.lastname: Catala
authors.forename: Manel
authors.initials: M
authors.lastname: Esteller
authors.forename: Felipe
authors.initials: F
authors.lastname: Prósper
authors.forename: María José
authors.initials: MJ
authors.lastname: Calasanz
authors.forename: Ismael
authors.initials: I
authors.lastname: Buño
authors.forename: Mi
authors.initials: M
authors.lastname: Kwon
authors.forename: Franck
authors.initials: F
authors.lastname: Court
authors.forename: Reiner
authors.initials: R
authors.lastname: Siebert
authors.affiliation: Imprinting and Cancer group, Cancer Epigenetic and Biology Program, Institut d'Investigació Biomedica de Bellvitge, Hospital Duran i Reynals, Av, Gran Via de L'Hospotalet 199-203, 08907 L'Hospitalet de Llobregat, Barcelona, Spain. dmonk@idibell.cat.
authors.forename: David
authors.initials: D
authors.lastname: Monk
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017398:Alternative Splicing; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D018922:HL-60 Cells; D019337:Hematologic Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D020014:K562 Cells; D007951:Leukemia, Myeloid / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011401:Promoter Regions, Genetic / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D020298:U937 Cells; D025721:WT1 Proteins / Q000235:genetics* / Q000378:metabolism; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D025721:WT1 Proteins