Chronic Myeloproliferative Disorders CMPDs, which were first reported by
Dameshek in 1951, are clonal hematopoietic stem cell disorders characterized by
proliferation of 1 or more myeloid cell lineages in the bone marrow and increased
numbers of mature or immature cells in peripheral blood. According to the Word
Health Organization, CMPDs or Myeloproliferative Neoplasms MPNs, include
Polycythemia Vera (PV), Essential Thrombocythemia (ET), Idiopathic
Myelofibrosis (IMF), plus rarer subtypes such us chronic neutrophilic leukaemia
(CNL), hypereosinophilic syndrome (HES) and chronic eosinophilic leukaemia
(CEL).
The identification in 2005 of the V617F mutation in the JAK2 gene in Chronic
Myeloproliferative Disorders (CMPDs) or Myeloproliferative Neoplasms (MPNs )
may explain several characteristics of these diseases and provide a prognostic
marker in clinical practice. The JAK2V617F mutation is present in 90% of
Polycythemia Vera, PV, patients and in about a half of Essential
Thrombocythemia, ET, and Idiopathic Myelofibrosis, IMF, patients respectively.
The purpose of this study was the investigation of the V617F mutation of the
JAK2 and the investigation of the over expression of PRV-1 gene in our
patients. Also we try to understand the mechanism of the over expression of
PRV-1 gene in the signalling pathway and the role in the pathogenesis of PV
patients. To achieve this goal we used specific tyrosine kinase inhibitors, in
specific cell lines (K562, HEL), such us Imatinib, Dasatinib, Sutent, Sorafenib
and Erlotinib. Another purpose of this study was the investigation of the over
expression of PRV-1 gene in patients, negative for the for the JAK2V617F
mutation, and positive for the mutation in the exon 12 of the JAK2 gene. Also
another purpose, was the investigation of the over expression of PRV-1 gene in
patients, negative for the for the JAK2V617F mutation, and positive for the
mutation in the thrombopoietin receptor c-MPL
We took advantage of our patients and analyzed them for the identification of
the V617F mutation and for the mutation load of the alleles carrying the V617F
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mutation. The identification of the V617F mutation was detected by
Amplification Refractory Mutation System-polymerase chain reaction (ARMs-
PCR) assay performed in DNA samples extracted from mononuclear cells from
the peripheral blood. This PCR assay allows detection of the mutation with
sensitivity about 1-2% (Jones et al, 2005).
The conclusions of our study:
?? Investigation of the JAK2V617F mutation and over expression of the PRV-1
gene in all our samples. Over expression of the PRV-1 in the positive
homozygote samples more than heterozygote sample. (p : 0.0004).
?? Investigation of the mutation in the exon 12 of the JAK2 gene. Over expression of the PRV-1
gene in these 5 positive samples, similarity with the over expression
observed in the positive PV samples for the JAK2V617F mutation.
?? Investigation of the mutation in the thrombopoietin receptor c-MPL (24
positive samples- 23 with ET and 1 with IMF). Also 20 patients were positive
for the W515L and 4 for the W515K mutation. Over expression of the PRV-1
gene in these 24 positive samples, similarity with the over expression
observed in the positive ET and IMF samples for the JAK2V617F mutation.
?? The purpose of this study was the investigation of the role of the HU in 7
PV patients and the role of this agent in the reduction of the over
expression of the PRV-1 gene. We found that HU can not reduced the
mutation load of the JAK2V617F mutation and it has none effect in the over
expression of the PRV-1 gene. The conclusion, of the purpose of this study,
has been carried out in 5 PV patients treated with the pegylated forms of
the IFN-a-2a. The reduction of the mutation load started during the first
year and it became undetectable after the 24 months of treatment a trend
reported in (Kiladjian et al, 2008). Also we observed a reduction of the over
expression of the PRV-1 gene similarity with the reduction of the JAK2V617
F mutation. In the case in which the reduction of the JAK2V617 F mutation
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it became undetectable the level of the PRV-1 was normal. The level of these
two markers remain lower after the last treatment for a few months
?? .Investigation of the mechanism of the over expression of PRV-1 gene in the
signalling pathway. To achieve this goal we used specific tyrosine kinase
inhibitors, in specific cell lines (K562, HEL), such us Imatinib, Dasatinib,
Sutent, Sorafenib and Erlotinib. We found effect in the growth of the cell
line K562 by the agent Imatinib, Dasatinib, Sutent, Sorafenib and not by the
drug Erlotinib. We did not observed any effect at the over expression of
the PRV-1 gene. Also we searched the effect of these drug in the cell line
HEL. We found a positive effect in the growth of the cell line HEL and in the
over expression of the PRV-1 gene by the drug Dasatinib, Sutent, Sorafenib.
Εθνικό Κέντρο Τεκμηρίωσης και Ηλεκτρονικού Περιεχομένου (ΕΚΤ)
