Tyrosine kinase inhibitors in renal cell carcinoma

Current standard treatments for patients with metastatic (stage IV) renal cell carcinoma involve both surgical removal of tumors and treatment with biological agents such as interleukin 2 and/or IFN-alpha. Unfortunately, such approaches are inadequate for most patients with stage IV disease, the result is a median time to progression of 2 to 4 months and an overall survival of 6 to 17 months. Standard chemotherapy has been uniformly disappointing in this disorder. It is clear that new therapies are needed to approach these patients. Recently, a greater understanding of cancer genetics has led to the successful development of novel therapeutics directed against targets linked to specific types of cancer. During the past decade, researchers have identified the von Hippel-Lindau (VHL) gene as an important tumor suppressor in clear cell carcinoma of the kidney. Elucidation of the VHL gene product (pVHL) and its regulation of hypoxia-inducible factor signaling have created a potential genetic basis for growth factor-targeted strategies in this disease. This review will focus on the potential growth factor targets in clear cell carcinoma, their relation to VHL and hypoxia-inducible factor, and the clinical challenges that face their development.