IL6 and diffuse large B-cell lymphoma: To examine whether the humanization of IL‐6, which lacks species cross‐reactivity (Kishimoto, 2005), would provide critical signals necessary for DLBCL growth and survival, we injected luciferase‐expressing RC‐K8 or U‐2932 cells into MISTRG and MISTRG6 mice, compared their growth kinetics over time by IVIS, and assessed human cell engraftment by flow cytometric analysis at the study endpoint.