KLK3 and neoplasm: In a retrospective analysis of the efficacy of 225Ac-PSMA-617 treatment with three cycles of 100 kBq/kg body weight in a group of 40 heavily pre-treated patients with mCRPC, remarkable PSA and a radiological response indicating anti-tumor activity of 225Ac-PSMA-617 were shown; at this center most patients had previously received extensive pretreatment with docetaxel (70%), cabazitaxel (17.5%), abiraterone (85%) and enzalutamide (60%), in addition to standard therapies generally including prostatectomy, external beam radiation and androgen deprivation therapy.