ENG and neoplasm: Analysis of the expression of ACVRL1 and ENG, either alone or combined, in 20 human PanNETs and 9 metastases (cohort previously reported in [17]) was demonstrated to be highly correlated to an endothelial cell metagene consisting of CD34, CDH5 and PECAM1 (Figure 1A–1C), indicating an exclusive endothelial cell expression within the tumor neovasculature.