The authors wish to retract the 15 April 2007 paper cited above, prepublished on 5 December 2006. Figure 2A in the original manuscript was inappropriately reproduced from a previously published paper, namely Battagli C, Uzzo RG, Dulaimi E, Ibanez de Caceres I, Krassenstein R, Al-Saleem T, Greenberg RE, Cairns P. Promoter hypermethylation of tumor suppressor genes in urine from kidney cancer patients. Cancer Res. 2003;63(24):8695-8699. The image was provided by Dr Román-Gómez, who was deemed responsible for the misrepresentation and duplication of this figure following institutional investigation. The remainder of the manuscript has not been called into question; however, the article is retracted as a whole. All authors, other than Román-Gómez, agree to this retraction, deeply regret this event, and apologize to the readers, reviewers, and editors for publishing this erroneous image.