In vitro cytotoxicity experiments were carried out on prostate cancer cell lines with different PSMA levels (from 3.000 to 150.000 mAbs bound/cell); in addition, in vivo biodistribution and anti-tumor efficacy were analyzed after i.v. injection of 100–500 kBq/kg to mice bearing prostate cancer xenograft models. The gene discussed is FOLH1; the disease is prostate carcinoma.