FLT4 and Patent ductus arteriosus: Recent data demonstrate that lymphangiogenesis, facilitated by VEGFR-3 signaling, contributes to cancer dissemination [28, 29] and in PDA expression of VEGFR-3 ligands VEGF-C and VEGF-D has been shown to correlate with the rate of metastasis to lymph nodes [30, 31].