We sought to examine a possible benefit of tocilizumab monotherapy in MISTRG6 mice that harbor spleen‐ and bone marrow‐colonizing lymphomas due to intravenous transplantation of serially passaged primary DLBCL cells; this patient‐derived xenograft is positive for the IL‐6R and also positive for phosphorylated STAT3 (Fig 4). Here, IL6R is linked to diffuse large B-cell lymphoma.