IRF4 and diffuse large B-cell lymphoma: To further validate the essential role of IRF4 in BCL2‐induced SOX9 expression in DLBCL, we co‐transduced t(14;18)‐negative OCI‐LY3 (ABC) and SUDHL2 cells (ABC), two cells lines that exhibit high endogenous IRF4 level, with BCL2‐OE/shCtrl, BCL2‐OE/shIRF4#1 or BCL2‐OE/shIRF4#2 for 72 h.