Although the findings of the current study suggest a role of integrin α5/integrin β1 and the existence of interaction among fibronectin, Src, and TGF-β1 signaling, and that these components play roles in the development of RCC, the complicated phenomena remind us that the roles of other uncharacterized molecules should not be ignored. This evidence concerns the gene TGFB1 and renal cell carcinoma.