Estrogen Receptor ER antibody clone 6F11 is a 66-kDa protein that mediates the actions of estrogens in estrogen-responsive tissues. The ER gene consists of more than 140kb of genomic DNA divided into 8 exons. These translate into a protein with six functionally discrete domains, labeled A through F. This mouse monoclonal antibody has been established to work in formalin-fixed, paraffin-embedded tissues and has been published in breast cancer studies. The 6F11 clone has been shown to be superior to the 1D5 (Bevitt DJ et al.).