JAK3 and acute lymphoblastic leukemia: Additional mutations exclusively found in the subgroup of thymic T-ALL included BCL11B, TET2, MTOR, BCOR, and ZSRS2. In contrast, genes of the JAK/STAT pathway (JAK1, JAK3) and the PRC2 complex (EZH2, SUZ12) as well as the transcription factors ETV6 and RUNX1 were predominantly mutated in the immature T-ALL subgroup (Figure 1a).