AR and Familial prostate cancer: In the male population Prostate Cancer (PC) remains a burden accounting for 15% of all new cancer cases yearly.1 Localized PC can be successfully cured by radiation or surgery while locally advanced and metastatic PC diseases are treated mainly with androgen deprivation therapy (ADT).2–4 ADT aims at blocking the biological processes involving the androgen receptor (AR) protein by reducing the amount of androgen ligands like testosterone to so-called “castration levels” (i.e. very low levels) or by administrating antagonists of androgens.