Various embodiments of this invention relate generally to targeted activation and delivery of therapeutic drugs to cells that produce prostate specific membrane antigen (PSMA), prostate specific antigen (PSA) or human glandular kallikrein 2 (hK2). Various embodiments relate more specifically to PSA, hK2 or PSMA-specific peptide prodrugs that become activated to yield therapeutic drugs. Further aspects of various embodiments of the present invention also relate to methods and compositions for treating or preventing cancers and methods and compositions for detecting and/or imaging cancers. More particularly, the invention relates to methods and compositions of imaging subjects using PSA, hK2 or PSMA-specific peptide prodrugs.
