JAK1 and myeloproliferative neoplasm: Thus, JAK2/STAT signaling pathway plays a central role in the MPN pathophysiology5 and has been targeted by ruxolitinib, a selective JAK1/2 inhibitor approved for the treatment of intermediate and high-risk PMF and PV patients that provides some clinical benefits, but does not lead to complete remission of these diseases and fails to eliminate the malignant clone6–9.