Abnormalities affecting tyrosine kinase
signalling in atypical myeloproliferative
disorders
Abnormalities affecting tyrosine kinase
signalling in atypical myeloproliferative
disorders
The myeloproliferative disorders (MPDs) are a group of haematopoietic stem cell diseases,
characterised by proliferation of one or more cells of the myeloid lineage. Several lines of
evidence have highlighted the importance of aberrant tyrosine kinase signalling in the
pathogenesis of these disorders. Cloning of rare chromosomal translocations and point
mutation analysis in the MPDs has identified diverse deregulated tyrosine kinase genes,
notably PDGFRA, PDGFRB, FGFR1 and JAK2. However the majority of atypical MPDs
still remain to be characterised and identification of patients harbouring fusions,
particularly those involving the PDGF receptors is of increasing importance, as they are
likely to be responsive to targeted therapy with imatinib.
I am investigating MPD patients for abnormalities affecting tyrosine kinase signalling, and
have used three approaches, translocation cloning, expression analysis and SNP array
analysis to detect regions of loss of heterozygosity (LOH). Thus far, by translocation
cloning I have identified a previously undescribed partner gene fused to PDGFRB and two
new PDGFRA fusion genes. I have also designed two reverse transcriptase PCR (RT-PCR)
assays and a cDNA MLPA assay to detect over-expression of specific tyrosine kinases
screening approximately 200 patients. Each assay identified all patients previously
diagnosed with known fusions. Additionally, two patients identified with overexpression of
PDGFRB have been found to have cryptic ETV6-PDGFRB fusions and overexpression of
PDGFRA in one patient lead to the discovery of a previously undescribed fusion involving
a novel partner gene (KIF5B).
Recent evidence has indicated that acquired isodisomy is a novel mechanism by which
mutations in cancer may be reduced to homozygosity. Typically, acquired isodisomy is
associated with oncogenic changes rather than tumour suppressor genes, eg. the activating
JAK2 V617F mutation and 9p aUPD. I have undertaken a screen using Affymetrix 50K
SNP arrays for regions of acquired isodisomy as a means to identify genomic regions that
may harbour novel oncogenes in different subgroups of MPD patients. Large tracts of
homozygosity (defined as >20Mb running to a telomere), strongly suggesting acquired
isodisomy, were seen in 40% aMPD patients. The homozygous tracts encompassed diverse
genomic regions in aMPD, but two common regions (3 cases for each region) were
identified at 7q and 11q. Mutations in the CBL ubiquitin ligase gene were discovered in all
three aCML patients with 11q aUPD as well as in an additional 23 MPD patients following
further screening.
Hidalgo-Curtis, Claire
5aaa8cfa-7271-48ee-8538-27736ab3eaf2
May 2009
Hidalgo-Curtis, Claire
5aaa8cfa-7271-48ee-8538-27736ab3eaf2
Cross, N.
f87650da-b908-4a34-b31b-d62c5f186fe4
Grand, F.
26daee41-f8f8-4bae-910f-89579532ea62
Hidalgo-Curtis, Claire
(2009)
Abnormalities affecting tyrosine kinase
signalling in atypical myeloproliferative
disorders.
University of Southampton, School of Medicine, Doctoral Thesis, 389pp.
Record type:
Thesis
(Doctoral)
Abstract
The myeloproliferative disorders (MPDs) are a group of haematopoietic stem cell diseases,
characterised by proliferation of one or more cells of the myeloid lineage. Several lines of
evidence have highlighted the importance of aberrant tyrosine kinase signalling in the
pathogenesis of these disorders. Cloning of rare chromosomal translocations and point
mutation analysis in the MPDs has identified diverse deregulated tyrosine kinase genes,
notably PDGFRA, PDGFRB, FGFR1 and JAK2. However the majority of atypical MPDs
still remain to be characterised and identification of patients harbouring fusions,
particularly those involving the PDGF receptors is of increasing importance, as they are
likely to be responsive to targeted therapy with imatinib.
I am investigating MPD patients for abnormalities affecting tyrosine kinase signalling, and
have used three approaches, translocation cloning, expression analysis and SNP array
analysis to detect regions of loss of heterozygosity (LOH). Thus far, by translocation
cloning I have identified a previously undescribed partner gene fused to PDGFRB and two
new PDGFRA fusion genes. I have also designed two reverse transcriptase PCR (RT-PCR)
assays and a cDNA MLPA assay to detect over-expression of specific tyrosine kinases
screening approximately 200 patients. Each assay identified all patients previously
diagnosed with known fusions. Additionally, two patients identified with overexpression of
PDGFRB have been found to have cryptic ETV6-PDGFRB fusions and overexpression of
PDGFRA in one patient lead to the discovery of a previously undescribed fusion involving
a novel partner gene (KIF5B).
Recent evidence has indicated that acquired isodisomy is a novel mechanism by which
mutations in cancer may be reduced to homozygosity. Typically, acquired isodisomy is
associated with oncogenic changes rather than tumour suppressor genes, eg. the activating
JAK2 V617F mutation and 9p aUPD. I have undertaken a screen using Affymetrix 50K
SNP arrays for regions of acquired isodisomy as a means to identify genomic regions that
may harbour novel oncogenes in different subgroups of MPD patients. Large tracts of
homozygosity (defined as >20Mb running to a telomere), strongly suggesting acquired
isodisomy, were seen in 40% aMPD patients. The homozygous tracts encompassed diverse
genomic regions in aMPD, but two common regions (3 cases for each region) were
identified at 7q and 11q. Mutations in the CBL ubiquitin ligase gene were discovered in all
three aCML patients with 11q aUPD as well as in an additional 23 MPD patients following
further screening.
Text
FINAL_THESIS.pdf
- Other
More information
Published date: May 2009
Organisations:
University of Southampton
Identifiers
Local EPrints ID: 72798
URI: http://eprints.soton.ac.uk/id/eprint/72798
PURE UUID: 4eec278d-e857-44e1-8674-db397a7439c8
Catalogue record
Date deposited: 24 Feb 2010
Last modified: 14 Mar 2024 02:46
Export record
Contributors
Author:
Claire Hidalgo-Curtis
Thesis advisor:
F. Grand
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics