Abstract
Two monoclonal antibodies against MCF-7 human estrogen receptors were used for immunoperoxidase staining of paraffin sections of human breast cancer tissue. The staining was predominantly located in the nucleus of epithelial cells. Variation in the staining intensity was observed among individual cells. A significant positive correlation between the number of positively stained cells and cytosol estrogen receptor content (fmol of bound estrogen/mg of protein) was observed. The potential and the limitations of the present techniques are discussed.