The androgen receptor (AR) antibody reacts with full length and the A-form of the receptor. It is known to be highly specific and does not cross-react with estrogen, progesterone or glucocorticoid receptors. It has been reported that well-differentiated tumors show high expression of Androgen Receptor and poorly differentiated tumors show low to no expression. In prostate cancer, androgen has been proposed as a marker of hormone-responsiveness, as high expression of Androgen Receptor in biopsies may help identify patients that would respond to androgen ablation therapy. Other applications for Androgen Receptor antibody include breast cancer, Paget’s disease and dermatopathology.