IL6 and diffuse large B-cell lymphoma: MISTRG mice that had been humanized in this manner or that had additionally been genetically modified to express human IL‐6 from a knock‐in allele turned out to be even better hosts for DLBCL cell lines and primary cells, which, upon intravenous injection, engrafted in the bone marrow, spleen, and non‐lymphoid tissues such as kidneys, liver, and lung.