Flat dysplasia and/or CIS are thought to be the precursors of muscle-invasive urothelial carcinoma, and progress through the non-papillary pathway after the gradual accumulation of genetic alterations of TP53 mutations, excision repair 2 mutations, loss of heterozygosity in chromosome 9, and others [2,5,11,18,19]. The gene discussed is TP53; the disease is in situ carcinoma.