Volume 9, Number 2Review ArticlesUnderstanding the Natural Biology of Kidney Cancer: Implications for Targeted Cancer TherapyTreatment UpdateArie S BelldegrunAllan J PantuckTobias KlatteMark D KleidDuring the past several decades, there has been a significant increase in the understanding of the biology, clinical behavior, and prognostic factors of renal cell carcinoma (RCC). Such progress has led to greater sophistication in the diagnosis and classification of RCC. Here, we review recent advances in our knowledge of the biologic characteristics of RCC that have resulted in notable achievements in staging, prognosis, patient selection, and treatment. [Rev Urol. 2007;9(2):47-56]AngiogenesisGeneticsMolecular markersTargeted treatmentTumor-node-metastasis classification