Immunohistochemical Analyses of Estrogen Receptor, Progesterone Receptor and nmt55/p54nrb in a Human Breast Tumor. Human breast tumor tissue was fixed, embedded, sectioned and subjected to immunohistochemical analysis with antibodies to human estrogen receptor alpha (hERα), human progesterone receptor (hPR) and nmt55/p54nrb. Panel A represents immunostaining with monoclonal antibody EVG F9 raised against hERα. Panel B represents immunostaining with monoclonal antibody 4.14 raised against hPR. Panels C and D represent immunostaining with anti-nmt55/p54nrb polyclonal antibodies NMT-4 and NMT-5, respectively.