JAK1 and acute lymphoblastic leukemia: For example, B-ALL cases with CRLF2 rearrangements, JAK1/2 mutations [12], CDKN2A/B deletions [15], TP53 deletions/mutations [16], or CREBBP deletions/mutations [17] had inferior outcomes in terms of response to chemotherapy, overall survival, or incidence of relapse.