KDR and neoplasm: Of note, findings in the current study showing a lack of synergy between VEGFR2 and FGFR1/2 signaling during tumor growth are distinct from our previous study where Vegfr2 heterozygosity showed no effect on injury response, while Fgfr1/2 inactivation in endothelial and hematopoietic cells was required for neoangiogenesis in response to injury13.