Identification of a novel GOLGA4–JAK2 fusion gene in B‐cell acute lymphoblastic leukaemia

Summary Rearrangements of Janus kinase 2 (JAK2r) form a subtype of acute lymphoblastic leukaemia (ALL) associated with poor patient outcomes. We present a high‐risk case of B‐cell ALL (B‐ALL) where retrospective mRNA sequencing identified a novel GOLGA4–JAK2 fusion gene. Expression of GOLGA4–JAK2 in murine pro‐B cells promoted factor‐independent growth, implicating GOLGA4–JAK2 as an oncogenic driver. Cells expressing GOLGA4–JAK2 demonstrated constitutive activation of JAK/STAT signalling and were sensitive to JAK inhibitors. This study contributes to the diverse collection of JAK2 fusion genes identified in B‐ALL and supports the incorporation of JAK inhibitors into treatment strategies to improve outcomes for this subtype.