TK6/iRFP cells are derived from the human lymphoblastoid TK6 cell line by stably integration of a constitutive miRFP670 stably expression construct. TK6 cells are heterozygous for thymidine kinase (TK), are commonly used in research related to genotoxicity, mutagenesis, and DNA repair, as well as evaluating the safety of new drug candidates. TK6/iRFP cells stably stably express miRFP670, can be used for in vitro assays and in vivo imaging.