Cancers are described as wounds that do not heal, suggesting that the two share common features. By comparing microarray data from a model of renal regeneration and repair with reported gene expression in renal cell carcinoma (RCC), Riss et al., found two expression signatures: a predominant concordant signature and a lesser discordant one. The concordant gene signature supports the view of cancer as a wound. The discordant signature, however, points to processes, pathways, and genes that differentiate cancer from wounds. These observations provide a conceptual framework to understand the biology and diagnostic and therapeutic strategies of RCC and acute renal failure. For details, see the article by Riss et al. on page 7216 of this issue.