Although earlier studies using gain-of-function approaches reported anti-lymphangiogenic activities of ectopically added VASH1 in the mouse cornea and in tumour conditions (Heishi et al., 2010), our loss-of-function analysis in zebrafish suggests a selective pro-lymphangiogenic function of Vash1 by supporting lymphovenous specification. This evidence concerns the gene VASH1 and neoplasm.