Vascular endothelial growth factor C (VEGFC) is a protein that is a member of the platelet-derived growth factor/vascular endothelial growth factor (PDGF/VEGF) family. It plays key roles in the physiology and pathology of many aspects of the cardiovascular system, including vasculogenesis, hematopoiesis, angiogenesis and vascular permeability. To test the effect of VEGFC on cell proliferation of ECV304 endothelium cell line, cells were seeded into triplicate wells of 96-well plates at a density of 2,000cells/well and allowed to attach overnight, then the medium was replaced with serum-free standard DMEM prior to the addition of various concentrations of VEGFC. After incubated for 72h, cells were observed by inverted microscope and cell proliferation was measured by Cell Counting Kit-8 (CCK-8). Briefly, 10µL of CCK-8 solution was added to each well of the plate, then measure the absorbance at 450nm using a microplate reader after incubating the plate for 1-4 hours at 37°C. The dose-effect curve of VEGFC was shown in Figure 1. It was obvious that VEGFC significantly promoted cell proliferation of ECV304 cells. The ED50 for this effect is typically 0.304 to 1.339µg/mL.