JAK2 and essential thrombocythemia: However, Kramer et al.18 identified this mutation in a patient with Ph+ CML and since then few similar cases has been reported.19-25 Out of these, Boochia et al.19 and Bee et al.21 patients with Ph+CML had a prior history of PV whereas Jalledes et al22 and Curtin et al23 reported cases had pre-existing JAK2 V617F positive ET who later acquired Ph translocation.