Preclinical data shows that the increased growth potential of cells in the PAH lung is also reflected by expression of growth factor receptors, including platelet derived growth factor receptor (PDGF-R) [21], fibroblast growth factor receptor (FGF-R) [22] and epidermal growth factor receptor (EGF-R) [23]. The gene discussed is EGFR; the disease is pulmonary arterial hypertension.