HMGB1 and diffuse large B-cell lymphoma: DLBCL cells were treated with rituximab and/or IL-10, a stimulator for STAT3, and then co-stained with HMGB1 (red) and either STAT3-PS727 or STAT3-PY705 (green) antibodies (Figure 3A and 3B and Supplemental Figure 3).