SU-DHL-1/RFP cells are derived from the human histiocytic lymphoma SU-DHL-1 cell line by stably integration of a constitutive RFP stably expression construct. SU-DHL-1 cell line has a high proliferation rate and is used to study various aspects of lymphoma biology, including the mechanisms of tumor growth and the effects of treatments. SU-DHL-1/RFP cells stably express RFP, can be used for in vitro assays and in vivo imaging.