FLT4 and neoplasm: Considering that tumor cells, EC and LEC express ETBR and VEGFR-3 as well as their cognate ligands, and taking into account that β-arr1 may coordinate the cooperation between ETBR- and VEGFR-3-related pathways (46), it's tempting to speculate that β-arr1 may actively take part also to the ET-1/VEGF-induced bidirectional communications between LEC, EC, and tumor cells.