Engineered anti-prostate stem cell antigen (psca) antibodies for cancer targeting

Humanized antibody fragment that specifically binds antigen of stem cells of the prostate (PSCA) on the surface of cancer cells wherein said fragment is selected from the group consisting of scFv, an scFv (diabody) dimer, a dimer sc-Fv-CH3 (minibody), and scFv-Fc, and wherein said antibody fragment comprises the sequences of the regions of the variable light (VL) and variable heavy chain (VH) shown in figure 1.