Among a variety of pro-angiogenesis factors, VEGF has been recognized as a key factor involved in tumor angiogenesis, which is mainly secreted by tumor cells, has high specificity for endothelial cells, and plays an important regulatory role in tumor angiogenesis by binding to its receptor VEGFR2 on endothelial cells, so VEGF/VEGFR2 is a target of anti-angiogenic therapy 45. Here, KDR is linked to neoplasm.