PR(progesterone receptor), with 933-amino acid protein (about 110kDa), a member of the steroid receptor superfamily, mediates the physiologic effects of progesterone, PR is mediated by two functionally different isoforms of the progesterone receptor, the full length PR-B and the short form PR-A. The PR-A and PR-B proteins are 94 kDa and 114 kDa respectively. That are equimolar in the normal breast but dysregulated in advanced disease. PR is prognostic markers in breast cancers irrespective of the patient's progestational status Human progesterone.