Hyperactivation of STAT5 is also associated with other blood malignancies such as acute lymphoblastic leukemia (ALL), chronic myelogenous leukemia (CML), myeloproliferative neoplasms (MPNs), in addition to human tumors (breast, prostate, liver, etc.), and other cancers (5). Here, STAT5A is linked to myeloproliferative neoplasm.