Experimentation using JAK2-V617F-positive mice to investigate the role of platelets in various thrombosis models has provided heterogeneous results: In ET, the aberrant activation of the PI3 kinase/Rap1/integrin αIIbβ3 pathway leading to ex vivo platelet hypo-reactivity has been described [108]. The gene discussed is JAK2; the disease is essential thrombocythemia.