Briefly, the ER + breast cancer cell lines, T47D and ZR75, were co-transfected with the NNAT promoter-reporter construct, and plasmids that constitutively expressed E2F1, E2F4, NRF1, PPARα/RXR, PPARγ/RXR, or control (pLX304). Here, E2F4 is linked to breast cancer.