MCF7/RFP-Luciferase cells are derived from the human breast cancer cell line MCF7 by stably integration of a constitutive RFP-Firefly luciferase stably expression construct. MCF7 cells are estrogen receptor-positive (ER+), making them a valuable model for studying hormone-dependent breast cancers and testing estrogen-related therapies. MCF7/RFP-Luciferase cells stably stably express RFP and Firefly luciferase, can be used for in vitro assays and in vivo imaging.