FASN and cancer: To assess whether estradiol stimulation of FASN protein expression involved activation of FASN gene transcription, MCF-7 cells were co-transfected with a luciferase reporter gene containing a 178-bp fragment of the FASN gene promoter harboring all the elements necessary for high level expression in cancer cells, including a complex SREBP (sterol regulatory element binding protein)-binding site [39,40,41].