Indeed, a patient with widespread metastatic prostate cancer resistant to treatment with β-particle emitting, 177Lu-labeled PSMA-617, a radiopeptide targeted to prostate specific membrane antigen (PSMA), achieved a complete remission when treated with α-particle emitting, 225Ac-labeled PSMA-617 with disappearance of tumours on positron-emission tomography (PET) scans using [68 Ga]Ga-PSMA11 and serum prostate specific antigen (PSA) levels decreasing almost 3000-fold to < 0.1 ng/mL (Kratochwil et al. 2016). This evidence concerns the gene KLK3 and prostate cancer.