EDN1 and neuroendocrine neoplasm: Korse et al. found a temporary elevation in angiogenic growth factors (vascular endothelial growth factor (VEGF), endothelin-1 (ET-1) and C-terminal proendothelin-1 (proET-1)) in the blood in twelve patients with well-differentiated neuroendocrine tumours and liver metastases who had undergone hepatic artery embolisation [21].