3. AR receptor positivity of primary tumor cells or tumor cells of a metastatic site is required. It is strongly recommended that 4 unstained and freshly cut 3-4 μ slides from the primary tumor (or metastatic if the primary is not available) be submitted for IRCCS IRST Laboratorio di Bioscienze for confirmation of AR eligibility; however, if that is not possible, a formalin-fixed paraffin-embedded (FFPE) tissue block will be submitted .