FLT4 and neoplasm: In addition, these studies have shown that VEGF-C-overexpressing tumours increase intratumoral lymphangiogenesis by activating the VEGF-C/VEGFR-3 axis in lymphatic endothelial cells, enhancing metastatic spread via the lymphatics (Karpanen and Alitalo, 2001; Skobe et al, 2001).