Anti-FGFR4 / CD334 (U3-1784) is a human monoclonal antibody targeting FGFR4 (human fibroblast growth factor receptor 4), with potential antineoplastic activity. It blocks activation of FGFR4, which inhibits FGFR4-mediated signaling and leads to an inhibition of cell proliferation in FGFR4-overexpressing tumor cells. MW: 145.5 KD.