Relevant Findings: Using a transgenic model of prostate cancer that overexpressed hepsin in the prostate epithelium, 55% of the double transgenic LPB-Tag (SV40 large T antigen in the prostate epithelium)/PB-hepsin mice, but none of the single transgenic LPB-Tag or PB-hepsin animals, develop prostate cancer that metastasizes to liver, lung, and bone.