SU-DHL-6/RFP cells are derived from the human diffuse large B-cell lymphoma (DLBCL) cell line SU-DHL-6 by stably integration of a constitutive RFP stably expression construct. SU-DHL-6 has been used to investigate the biology of DLBCL, study the interactions between lymphoma cells and the immune microenvironment, and evaluate the effectiveness of various treatment approaches. SU-DHL-6/RFP cells stably express RFP, can be used for in vitro assays and in vivo imaging.