Eng acts as an auxiliary receptor for transforming growth factor-β (TGF-β), modulating several signaling pathways, and its overexpression is associated with dysregulated angiogenesis (195)—in PAH, enhanced Eng expression has been found in plexiform lesions, which is in favor of Eng as an indicator of vascular proliferation and remodeling (188). This evidence concerns the gene ENG and pulmonary arterial hypertension.