The development of a pterygium involvesgrowth factors such as heparin-binding epidermal growth factor (promotingangiogenesis and stimulating anchorage growth and cellular transformation), vascularendothelial growth factor (increasing vascular permeability, angiogenesis, andlymphangiogenesis), platelet-derived growth factor (promoting fibroblastproliferation), and trans forming growth factor beta (promoting angiogenesis andfibroblast activation with collagen production)(15,16). The gene discussed is HBEGF; the disease is pterygium.