Figure 1. DHT-dependent phase of PCa.
In this phase of PCa, some tumors rely mainly on DHT. The source of testosterone (T) is mainly from the testis and adrenal glands provide dehydroepiandrosterone (DHEA). Testosterone and DHEA are converted to DHT by 5-alpha reductases (SRD5A) present in the prostate. AR has higher affinity for DHT than testosterone. For this reason, finasteride and dutasteride, which inhibit type 1 or both type 1 and type 2 5-alpha reductase activity, respectively, can suppress tumor development or growth, accounting for suppression of low-grade cancers, but not high-grade cancers, in a proportion of men with PCa.