JAK2 and Thrombocytopenia: Moreover, we found that the activation of STAT3 by phosphorylation, as the downstream proteins of JAK2 for thrombopoiesis, were suppressed in megakaryocytes, which may broaden the understanding of pathways involved in CIT, and more importantly, raise the pre-cautions of thrombocytopenia about therapies aiming at JAK/STAT pathway.