KDR and cancer: Over the more recent years, embryonic zebrafish models gained traction in cancer research, due to several advantages compared to in vivo work in mice – key points are summarized here; embryonic zebrafish are transparent, easy to genetically manipulate – such as flk1::GFP transgenes leading to green colour of the endothelial cells – and provide the possibility to create cancer xenografts and follow their growth and physiological and pathological angiogenesis with advanced imaging techniques in high throughput (30, 32, 56).