MD.

The exact significance of the JAK2 V617F mutation in MDS is unclear. It has previously been suggested that MF could be associated with MDS as one phenotype of myeloproliferative disorders. Ohyashiki et al in 2005 showed that two of six patients with MDS terminating in MF had the mutation at the time of MF, while no MDS patient without MF had the JAK2 V617F mutation, suggesting that MDS patients with the JAK2 V617F mutation may be responsible for secondary MF in MDS patients. We conducted the following experiments to further probe the role of JAK2 mutation in the pathology of MDS with myelofibrosis at our institution.

DNA samples of 8 patients in our institution who had MDS with subsequent myelofibrosis were isolated. Genomic DNA isolated using DN easy tissue kit(Qiagen) was amplified by PCR. After confirmation of DNA presence on 1 % agarose gel and purification using QIA quick PCR purification kit (Qiagen), gene sequencing was done. This sequencing was then analyzed for G to T mutation V617F in JAK2.

We found no evidence of the JAK2 mutation in any of the eight samples.

Given the fact that nearly half the patients with myelofibrosis carry the JAK2 V617F mutation, the possibility of an association between those patients who have myelodysplasia and subsequent myelofibrosis needs to researched. Our cohort which consisted of 8 patients showed no evidence for any such correlation. This evidence confirms the presence of different pathophysiological mechanisms for phenotypic expression of MDS and primary MF and also leads us to suggest that the expression of JAK2 is not the driving mutation in the pathogenesis of MDS progression to myelofibrosis.

No relevant conflicts of interest to declare.