KDR and cancer: Furthermore, the consequence of VEGF signalling in a variety of tumours extends beyond merely recruiting endothelial cells and forming perfusion channels; signalling through both VEGF-Receptor 1 (VEGF-R1) and VEGF-Receptor 2 (VEGF-R2) has been implicated in cancer progression, together contributing to tumour cell invasion, migration, proliferation, and metastasis.