FLT4 and neoplasm: Tumor lymphangiogenesis is the first stage of LN metastasis, followed by tumor cell dissemination to the lymphatic vessels, tumor cell transfer to LNs through the lymphatic system, cell seeding, colonization, and growth in LNs [6] Vascular endothelial growth factor (VEGF-C) and VEGF-D as well as their cognate receptor VEGF-R3 have been reported to be crucial for the onset of lymphangiogenesis [7].