Literature survey on non-steroidal prostate cancer inhibitors demonstrated that the tetrahydrobenzo[4,5]thieno[2,3-c]pyridine derivatives, VIIa–d, exhibited a comparable potency to abiraterone in inhibiting rat CYP17 enzyme and were able to decrease plasma testosterone level in a dose-dependent manner26 (Figure 1). This evidence concerns the gene CYP17A1 and prostate cancer.