The present invention relates to the use of Fibroblast-Growth Factor Receptor (FGFR) agonists for the diagnosis, prevention and/or treatment of pathological conditions including, but not limited to hyperproliferative disorders, bone diseases and vascular diseases. Particularly, the use of FGFR-4 agonists, e.g. anti-FGFR-4 antibodies is described. Further, the invention relates to a pharmaceutical composition comprising the agonist as described above and a screening procedure.