However, genetic ablation of itgb3, itgb5 or both simultaneously accelerates tumour vasculature growth and development, attributable to the increased expression of vascular endothelial growth factor receptor 2 (VEGFR2) and sensitivity to VEGF-A (discussed by Silva et al. 2008) suggesting that these integrins are not required for blood vessel formation but regulate their rate of growth. This evidence concerns the gene KDR and neoplasm.