However, only limited multiple-pathological-insult rat models of PAH have been shown to develop complex plexiform-like lesions, such as monocrotaline (MCT) combined with pneumonectomy [17] or chronic hypoxia [18], or SU5416 (a tyrosine-kinase inhibitor of VEGFR-2) with chronic hypoxia [19] or pneumonectomy [20], providing evidence that severe hypoxia and VEGF/VEGFR-2 signaling dysregulation are required for the development of plexiform lesions. The gene discussed is KDR; the disease is pulmonary arterial hypertension.