In humans, the CYP17A1 gene is largely associated with endocrine effects and steroid hormone metabolism.    Furthermore, mutations in the CYP17A1 gene are associated with rare forms of congenital adrenal hyperplasia, in particular 17α-hydroxylase deficiency/17,20-lyase deficiency and isolated 17,20-lyase deficiency. Overall, CYP17A1 is an important target for inhibition in the treatment of prostate cancer because it produces androgen that is required for tumor cell growth.   Currently, the FDA has approved only one CYP17A1 inhibitor, abiraterone, which contains a steroidal scaffold that is similar to the endogenous CYP17A1 substrates. Abiraterone is structurally similar to the substrates of other cytochrome P450 enzymes involved in steroidogenesis, and interference can pose a liability in terms of side effects. Using nonsteroidal scaffolds is expected to enable the design of compounds that interact more selectively with CYP17A1.  Potent inhibitors of the CYP17A1 enzyme provide a last line defense against ectopic androgenesis in advanced prostate cancer. 
Tetrahydrogestrinone (THG) - Commonly known as The Clear, Tetrahydrogestrinone (THG is a type of steroid that had only been recently placed into scheduling as of 2005 and is noted unapproved by FDA. It basically binds with the androgen receptor instead of estrogen which makes it effective in increasing endurance for athletes. According to history, this was the secret of winning for the gold medalist Marion Jones, a sprinter athlete. However, longer association with this type of steroid can lead to infertility in both male and female. Using the steroids abuse test kit, a person may be held liable for a positive THG steroid test.