JAK1 and acute lymphoblastic leukemia: The semi-selective JAK1/2 inhibitor, ruxolitinib, is currently being assessed in a number of clinical trials (NCT02723994, NCT03117751, NCT03571321, NCT02420717) for the treatment for ALL after promising efficacy was demonstrated in several pre-clinical models (Maude et al., 2012; Roberts et al., 2014a; Roberts KG.