ETS1 and breast cancer: In addition, because both the PEA-3 and ETS-2 ETS factors have been implicated in human breast cancer (although neither contains a SAR domain) we also fused GFP, in-frame, to the N-terminus of each of these ETS proteins and used these two fusions to test both their transforming potency and to control for nonspecific transforming effects of ETS protein expression in MCF-12A cells.