JAK2 and essential thrombocythemia: In contrast to both studies is a microarray gene expression analysis in 93 patients with MPNs (28 PV, 47 ET and 18 MF) in comparison to granulocytes of 11 age-matched normal donors; although this led to the identification of a characteristic gene expression profile related to JAK2 activation in MPN patients, it did not identify a specific expression signature derived from the JAK2-mutational state [61].