CYP17A1 and Familial prostate cancer: One of the principle mechanisms involves aberrant intracrine signaling due to increased activity of androgen-biosynthesis enzymes, such as the steroidogenic enzyme cytochrome P450 17A1 (CYP17A1), allowing prostate cancer cells to utilize dehydroepiandrosterone (DHEA), the adrenal androgen precursor for the synthesis of bioactive dihydrotestosterone (DHT).