Recent years, LYVE-1 (1999, Banerji et al.), podoplanin (1999, Breiteneder-Geleff et al.) and Prox-1 (1999, Wifle & Oliver) were found one after another as specific antigens of lymphatic endothelium and the approach to lymphatic study has progressed dramatically. However, it has been reported that these antigens are not expressed in only lymphatic endothelium according to tissues or clinical conditions, but antibodies against these antigens also react with other vessels especially vascular endothelium.