It has been reported that the average number of methylated tumor-related genes and the expression level of DNMT1 protein are increased in non-cancerous urothelia showing no marked histological findings from patients with urothelial carcinomas, in comparison with normal urothelia from patients without urothelial carcinomas (Nakagawa et al., 2005). This evidence concerns the gene DNMT1 and urothelial carcinoma.