KDR and arthritic joint disease: One study revealed that the VEGFR signal-transduction process regulates the biological responses to VEGF.[20] Therefore, the correlation between VEGF with VEGFR2 is important in angiogenesis.[21] Furthermore, VEGFR2 accounts for the majority of the angiogenic and permeability-enhancing effects of VEGF.[22] Angiogenesis plays an important role in the pathogenesis of various diseases, such as cancer, arthritis, and autoimmune conditions.[23,24,25,26]