The primitive, stem cell-like ECs also expressed CD117, a marker of primitive hematopoietic and endothelial cells and incidentally, CD117+ lesion cells occur in the occlusive pulmonary arteriopathy in human PAH and severe pulmonary hypertension (PH) induced by chronic hypoxia and SU5416 in rats5,17,19,20. This evidence concerns the gene KIT and pulmonary arterial hypertension.