A significant proportion of unmutated STAT3 LGL leukemia cases also features hyperactivation of the JAK/STAT pathway by two mechanisms (19); i) underexpression of the SOCS3 (suppressor of cytokine signaling-3) gene, ii) excess autocrine production of interleukin-6 by NK-LGLs. The gene discussed is SOCS3; the disease is leukemia.