Abiraterone is an example of an irreversible inhibitor of CYP17A1 and can reduce tumor burden, prolong life and relieve symptoms as it inhibits both the 17α-hydroxylase and 17,20-lyase activities of CYP17A1 and therefore inhibits multiple steps in androgen biosynthesis8,9. This evidence concerns the gene CYP17A1 and neoplasm.