title: The complex genomic profile of ETV6-RUNX1 positive acute lymphoblastic leukemia highlights a recurrent deletion of TBL1XR1.
abstract: The ETV6-RUNX1 fusion is the molecular consequence of the t(12;21)(p13;q22) seen in approximately 25% of children with acute lymphoblastic leukemia (ALL). Studies have shown that the fusion alone is insufficient for the initiation of leukemia; additional genetic changes are required. Genomic profiling identified copy number alterations at high frequencies in these patients. Focal deletions of TBL1XR1 were observed in 15% of cases; 3 patients exhibited deletions distal to the gene. Fluorescence in situ hybridization confirmed these deletions and quantitative RT-PCR showed that the TBL1XR1 gene was significantly under-expressed. TBL1XR1 is a key component of the SMRT and N-CoR compressor complexes, which control hormone-receptor mediated gene expression. Differential expression of the retinoic acid target genes, RARB, CRABP1, and CRABP2, indicated that deletion of TBL1XR1 compromised the function of SMRT/N-CoR in the appropriate control of gene expression. This study identifies deletions of TBL1XR1 as a recurrent abnormality in ETV6-RUNX1 positive ALL. We provide evidence that implicates this deletion in the inappropriate control of gene expression in these patients. The target of the interaction between TBL1XR1 and the signaling pathways described here may be exploited in cancer therapy.
authors.affiliation: Leukaemia Research Cytogenetics Group, Cancer Sciences Division, University of Southampton, Southampton, UK.
authors.forename: Helen
authors.initials: H
authors.lastname: Parker
authors.forename: Qian
authors.initials: Q
authors.lastname: An
authors.forename: Kerry
authors.initials: K
authors.lastname: Barber
authors.forename: Marian
authors.initials: M
authors.lastname: Case
authors.forename: Teresa
authors.initials: T
authors.lastname: Davies
authors.forename: Zoë
authors.initials: Z
authors.lastname: Konn
authors.forename: Adam
authors.initials: A
authors.lastname: Stewart
authors.forename: Sarah
authors.initials: S
authors.lastname: Wright
authors.forename: Mike
authors.initials: M
authors.lastname: Griffiths
authors.forename: Fiona M
authors.initials: FM
authors.lastname: Ross
authors.forename: Anthony V
authors.initials: AV
authors.lastname: Moorman
authors.forename: Andy G
authors.initials: AG
authors.lastname: Hall
authors.forename: Julie A
authors.initials: JA
authors.lastname: Irving
authors.forename: Christine J
authors.initials: CJ
authors.lastname: Harrison
authors.forename: Jon C
authors.initials: JC
authors.lastname: Strefford