VEGFA and neoplasm: Interestingly, whereas VEGF-Axxx isoforms are pro-angiogenic and are up-regulated in tumours, in vitro and in vivo studies demonstrated that VEGF-Axxxb isoforms (e.g. VEGF-A165b and VEGF-A121b) are anti-angiogenic and down-regulated in tumours (36,40,41).