KDR and neoplasm: Additionally, VEGF and its cognate receptor VEGFR-2 activate alphaVbeta3 (ɑvβ3) and alphaVbeta5 (ɑvβ5) integrins to migrate toward SPARC in bone, thereby promoting tumor growth, neo-angiogenesis, and development of the metastatic tumor (De et al., 2003).