Interestingly, the TKI ruxolitinib was the first small molecule inhibitor of JAK1/2 kinases which was used in the treatment of myelofibrosis, applied to the field of myeloproliferative neoplasms[46] and as a result of the promising results achieved in clinical trials, approved for the treatment of myelofibrosis by the U.S. FDA[47,48]. Here, JAK1 is linked to myelofibrosis.