In the majority of cases of RCC, functional inactivation of the von Hippel–Lindau (VHL) gene leads to overexpression of hypoxia inducible factor (HIF)-1α and HIF-2α resulting in overproduction of vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-α (Kim and Kaelin, 2006). Here, TGFA is linked to renal cell carcinoma.