VEGFA and neoplasm: In conclusion, platelets not only directly surround CTCs to protect them from clearance by flow shear stress and immune cells in the bloodstream, participate in tumor neovascularization by transporting cytokines such as VEGF and provide sufficient nutrients for tumor progression, but also facilitate adhesion to the endothelium and transendothelial migration of CTCs by regulating tumor vascular integrity, eventually leading to metastasis and colonization.