In a recent issue of Blood Research, Song and colleagues highlighted the number of patients with cerebral infarctions and either erythrocytosis or thrombocytosis in whom further investigation of a myeloproliferative neoplasm (MPN) was not sought . Extrapolated globally, where the lifetime risk of stroke is approximately 25%, this seemingly small number of patients with an underlying MPN would represent a considerable proportion of worldwide stroke cases in which intervention with specific MPN-directed therapies, both established and novel, would be missed [2, 3].
This important finding raises some considerations. In addition to improved communication between hematologists and neurologists, would the authors suggest implementation and justification of an MPN-associated molecular screening programme for all patients with stroke, regardless of the presence of an erythrocytosis or thrombocytosis? Furthermore, the vast majority of MPN patients presenting with stroke have molecular evidence of the JAK2 V617F mutation, however rare cases harboring JAK2 exon 12, MPL exon 10 and CALR exon 9 mutations have been reported [4, 5, 6]. Would the authors therefore consider incorporating these other MPN-associated driver mutations into any molecular screening programme? As MPN-directed therapy should be regarded as an integral component of secondary stroke prevention , identification or exclusion of this underlying malignant cause should be a priority.