The mAbs anti-VEGFR-3, IMC-3C5, and small bivalent antibody constructs (diabody) directed against VEGFR-2/VEGFR-3 have been developed and are in clinical trial phase I [85,86], while the fusion protein VEGFR-31-ig and the soluble VEGFR-3 decoy receptor are in the preclinical study phase for the treatment of HCC [87], prostate cancer, and melanoma [88], respectively. Here, FLT4 is linked to prostate carcinoma.