Studies in animal models have also shown that tumor relapse on abiraterone was associated with further upregulation of intratumoral CYP17 and other key genes involved in intratumoral androgen synthesis after abiraterone therapy.45,49 These include the target gene CYP17A1, as well as CYP11A1, AKR1C3, and HSD17B3 genes. The gene discussed is CYP17A1; the disease is neoplasm.