Most of the previous in vitro studies on breast cancers have employed DHT (a non-aromatizable form of testosterone) or R1881 (a non-aromatizable synthetic analogue of testosterone) as an agonist for AR, but under normal physiological conditions body has other different androgens like dehydroepiandrosterone (DHEA), androstenedione, androstenediol (A5), androsterone, and DHT; and their binding capacities may different (Table 1). The gene discussed is AR; the disease is breast carcinoma.