To develop a system to test functionality of the four STAT3 variants, we used two representative ABC DLBCL cell lines, OCI-Ly10 and HBL1, in which high activity of STAT3 is driven by the autocrine cytokines IL-6 or IL-10 and promotes cell survival and proliferation.6, 11, 24 The GCB cell line OCI-Ly19 with no constitutive STAT3 activation served as a control. The gene discussed is IL10; the disease is diffuse large B-cell lymphoma.