JAK2 and myeloproliferative neoplasm: Janus kinase (JaK) is a class of non-receptor tyrosine kinase and the dysregulation of JaK2 signaling due to mutation causes various myeloproliferative neoplasms.56 Gandotinib 49 is janus kinase 2 (JAK2) inhibitor that is being developed by Eli Lilly to treat various myeloproliferative neoplasms (MPNs).