Because of the high frequency of mutations in the JAK-STAT system, the authors examined the levels of inflammatory cytokines and found that the plasma IL-10 levels were significantly elevated in ANKL patients and that activation of the JAK/STAT system in ANKL led to an increased expression of MYC, implying the importance of IL-10-STAT3-MYC transcription regulation in ANKL. This evidence concerns the gene MYC and aggressive NK-cell leukemia.