STAT5A and acute lymphoblastic leukemia: For example, the importance of JAK/STAT in early T-cell precursor (ETP) acute lymphoblastic leukemia (ALL) has been confirmed when the JAK1/2 inhibitor ruxolitinib has been used in murine xenograft models leading to abrogation of the STAT5 activation in response to IL-7 (Maude et al., 2015).