MM.1R/Cre cells are derived from the human B lymphoblast MM.1R cell line by stably integration of a constitutive Cre recombinase stably expression construct. MM.1R cells have been used in to study the molecular and cellular mechanisms that drive multiple myeloma progression, and test the efficacy of new drugs or treatment strategies for multiple myeloma. MM.1R and MM.1S, were independently created from the parental cell line MM.1 to represent models of resistance and sensitivity, respectively, to dexamethasone. MM.1R/Cre cells stably express a nuclear localized Cre recombinase.