Human fibroadenoma (serial sections): immunohistochemical staining for Progesterone Receptor (A and B forms). Note a smaller proportion of weakly staining tumor cell nuclei in A compared to B. Progesterone Receptor (A/B Forms): clones 16/SAN27
Progesterone Receptor (A/B Forms)
Antigen Background The human progesterone receptor (PR) is expressed as two isoforms, PRA (94 kD) and PRB (114 kD), which function as ligand-activated transcription factors. In vitro studies have indicated that PRA and PRB can activate different target genes and that PRA, in some circumstances, may act as a dominant inhibitor of the function of PRB and other steroid hormone receptors. PRA and PRB are both expressed in normal breast. Most endometrial carcinomas, however, are reported to express only one isoform with either PRA or PRB being expressed.
Product Specific Information The cocktail has been formulated using two clones, clone 16, specific for PRA, and SAN27, specific for PRB.
Disclaimer Progesterone Receptor (A/B Forms) is recommended for the detection of specific antigens of interest in normal and neoplastic tissues, as an adjunct to conventional histopathology using non-immunologic histochemical stains.