Genetics, structure, function, mode of actions and role in cancer development of CYP17.

Most prostate and breast cancers are hormone dependent. The inhibition of steroid 17α-hydroxylase/17,20- lyase (CYP17), which is a crucial enzyme for steroid hormone biosynthesis, is widely used to treat androgen-dependent prostate cancer (PC). CYP17 has dual enzymatic activity: 17alpha-hydroxylase activity (utilizing delta4- C21 steroids as substrates) and the 17,20-lyase activity (using delta5- C21 steroids as substrates).